Swahili is a Bantu language which is native to or mainly spoken in the East African region. It has a grammatical structure that is typical for Bantu languages, bearing all the hallmarks of this language family. These include agglutinativity, a rich array of noun classes, extensive inflection for person (both subject and object), tense, aspect and mood, and generally a subject–verb–object word order.

Typology

Swahili may be described in several ways depending on the aspect being considered.

• It is an agglutinative language. It constructs whole words by joining together discrete roots and morphemes with specific meanings, and may also modify words by similar processes.
• Its basic word order is SVO. However, because the verb is inflected to indicate the subject and sometimes also the object, this order may be changed to emphasise certain parts of the sentence.
• It does not mark nouns for case. Nominal roles are indicated by a combination of word order and agreement markers on the verb, with no change to the nouns themselves.
• It has a complex grammatical gender system, but as this does not include a distinction based on natural sex, the term "noun class" is generally used instead of "gender".
• It has head-first order with few exceptions.
• It is a pro-drop language. Verbs may be used without explicitly specifying the subject or the object with substantives (nouns or pronouns).

Nouns

Noun classes

Swahili nouns are grouped into noun classes based on the prefix they have, with each class having a prescribed number. For example, the nouns wasichana "girls" and wasimamizi "overseers" belong to class 2, characterised by the prefix wa-, whereas kifuniko "lid, cover" and kisukari "diabetes" belong to class 7, characterised by the prefix ki-. The classes 5, 9 and 10 are frequently without any prefix, such as gari a class-6 noun meaning "car" and chupa, meaning "bottle" in class 9 and "bottles" in class 10. The numbers are based on the classes reconstructed for Proto-Bantu, and have corresponding classes in the other Bantu languages which can be identified by the same system of numbers. Therefore, classes that are missing in Swahili create a gap in the numbering, as is the case with classes above 18 as well as classes 12 and 13, which are absent in standard Swahili (although do frequently occur in non-standard varieties). Tables in this article are labelled not only with the traditional numbering system for Bantu languages but also a simple label based on noun morphology in order to make the tables more accessible to learners, who are generally taught labels for classes such as "ki/vi" instead of "7/8".

When discussing Swahili noun classes, it is important to distinguish between (1) morphological noun classes as a quality of the noun themselves indicated by morphological features (generally prefixes), and (2) syntactic noun classes as an agreement (i.e. concord) paradigm affecting the use of other words in the sentence. Here, "noun class" is used with the former meaning. Morphological and syntactic noun classes often diverge, especially when it comes to nouns referring to people and animals which do not belong to the morphological noun class 1/2, signalled by m-wa. For more information, see concord.

The following noun classes exist:

1. This m- before a consonant is always syllabic /m̩/, even when the following consonant is b or v, as in mvulana "boy" [m̩.vu.ˈlɑ(ː).nɑ]. The mw- before a vowel, however, is not syllabic, as in mwalimu "teacher" [mwɑ.ˈli(ː).mu]. When the stem is only one syllable, the prefix takes the stress, as in mtu "person" [ˈm̩.tu]. Before a stem beginning with u, the prefix may appear as either mw- or mu-, as in mwuguzi / muuguzi "nurse". A few nouns, mostly loans, have mu- before a consonant, such as muziki "music", musuli "muscle" and muda "length of time" (although mziki, msuli and mda are also widespread variations). In class 3, the w is frequently absent before o as in moyo "heart" (plural: mioyo), moto "fire" (plural: mioto) and moshi "smoke".
2. Wa- is often present only as w- when the stem begins with /a/ as in wanafunzi "students" (singular: mwanafunzi). A following i may merge with the a of this prefix, forming we- as in wezi "thieves" (singular: mwizi). The a in this prefix is generally preserved in nouns which are derived from verbs, such as waandishi "writer" (singular: mwandishi, from the verb ‑andika "to write"), as well as those derived from proper nouns, such as Waafrika "Africans" (singular: Mwafrika) and Waislamu "Muslims" (singular: Mwislamu).
3. The ji- prefix occurs on nouns with monosyllabic stems, such as jiwe "stone" (plural: mawe), but is absent from longer words. This is not to be confused with the augmentative prefix ji-, which is not dropped in the plural, for example jiji "large town, city" (plural: majiji, from mji "town"). Some nouns may also simply have stems which start with ji- such as jina "name" (plural: majina). Some words whose stems begin with a vowel take the prefix j-, such as jambo "thing, affair" (plural: mambo) but others do not, such as azimio "resolution" (plural: maazimio).
4. The prefix ma- may merge with a following i to become me- as in meno "teeth" (singular: jino).
5. The prefixes ki- and vi- may sometimes appear before vowels, such as in kiazi "potato" (plural: viazi) rather than the possibly expected *chazi and *vyazi. It is possible to regard the stem of these words as beginning with the i (e.g. ‑iazi) as adjectives beginning with i, such as ‑ingine "other" simply take k- and v- prefixes in these classes.
6. The n of the prefix is a prenasalising mutation of the following consonant and is never syllabic unless the noun would otherwise only have one syllable. It becomes m before b and v. In stems beginning with w such as ‑wili "two", this mutates to mb. Before vowels it is present as ny. Before d, z, j and g it is n. L and r become nd. Before other consonants, it disappears unless it is required as a syllabic consonant to prevent the noun from having only one syllable, such as in nchi "country, land". The plural form of class 11 nouns is formed this way, dropping the u- and then applying these rules (for example ulimi → ndimi "tongue" → "tongues", ukuta → kuta "wall" → "walls"), except that short nouns with a monosyllabic stem preserve the u- in the plural for reasons of stress, adding ny- before it to form the plural, such as uso "face", which becomes nyuso in the plural.
7. The u- prefix has some variation in spelling and pronunciation before vowels.
8. The ku- prefix becomes kw- only before a minority of stems: kwenda "to go" and kwisha "to finish".
9. The locative classes of nouns no longer have their original pa-, ku-, m(u)-prefixes in Swahili, with these only appearing on adjectives, demonstratives and other parts of the grammar. Most nouns form their locative form by adding the suffix -ni although this cannot be added to geographical place names, many recent loans and certain other words.

Every class up to 11 can be regarded as inherently singular or plural. Odd-numbered classes are singular, even-numbered classes are plural. The plural of a noun is normally formed by switching it to the next higher class. Thus, the plural of class 1 mtu "person" is class 2 watu "people". For class 11 nouns, the plural is in class 10. Class 14 usually has no plural at all, but in rare instances class 6 is used to form a plural for these nouns, for example ugonjwa "sickness, disease", magonjwa "diseases". Class 6 also contains a lot of nouns for liquids, such as maji "water", and other nouns derived from verbs such as mazungumzo "conversation(s)". Aside from these, there are some nouns in other classes that do not change class to indicate number, such as mchana "afternoon(s)", "daytime" (class 3), vita "war(s)" (class 8), usiku "night(s)" (class 14), and these can be shown as singular or plural only by surrounding context.

In terms of meaning, groups of similar nouns tend to belong to similar noun classes. For example, nouns for people, including agent nouns, are commonly in classes 1/2, while animals are often in classes 9/10. Nouns describing plants are in class 3/4 and any fruit they produce will probably be in class 5/6. Abstract nouns are often in class 14, loanwords in classes 9/10 and 5/6. Many nouns for liquids are in class 6. Infinitives/gerunds of verbs are in class 15. Diminutives as well as the words for many man-made tools and languages are in class 7/8. These are only generalisations and there are exceptions in most classes.

Concord

The class of the noun determines the forms of other parts of speech that relate to it, such as verbs, adjectives, etc. This process is called agreement or concord. These other parts of speech receive their own concordant prefixes (termed "concords" for short), generally matching in class with the noun, though the prefixes themselves are not always the same. In the examples below, the left and right sides of the table show sentences with a singular and then plural subject respectively.

Animate nouns (i.e. those referring to people or animals) which are not in classes 1/2 generally take the agreement prefixes (concords) from classes 1/2 as if they did belong to it.

Animacy agreements can often distinguish different meanings of the same noun, such as ndege, which means "bird(s)" when animate and "aeroplane(s)" when inanimate.

Animate nouns in classes 9/10 may exhibit a slight aberration from this pattern. The genitive pronominal forms -angu, -ako, -ake, -etu, -enu and -ao are frequently inflected with a group of nouns referring to close human relationships with their appropriate class 9/10 concords, regardless of the fact that they are animate (giving yangu, yako, yetu etc. in singular and zangu, zako, zetu etc. in plural). For some speakers, the same rule applies to the simple genitive preposition -a (giving ya in singular and za in plural), however for most speakers wa is used for all animate nouns regardless of number or class. Other parts of speech are unaffected by this exception.

Nouns which follow this pattern of agreement include mama "mother(s)", baba "father(s)", ndugu "sibling(s)/relative(s)", kaka "(elder) brother(s)", dada "(elder) sister(s)", nyanya "grandmother(s)", bibi "grandmother(s)", babu "grandfather(s)", shangazi "paternal aunt(s)", shemeji "sister(s)/brother(s)-in-law", wifi "sister(s)-in-law", jamaa "relative(s)", rafiki "friend(s)", shoga "female friend of a woman", jirani "neighbour" and adui "enemy".^[1]

Nouns of this group, such as rafiki "friend", may optionally take a plural prefix ma- as though belonging to class 5/6, although their concords remain the same mix of class 1/2 and 9/10.^[2]

In addition, animals of classes 9/10 generally take class 1 agreement throughout the singular, but may take 10 agreement on pronominal genitive words in the plural.

Another departure from the rule of animate nouns taking concords in classes 1/2 occurs on occasion with diminutives and augmentatives, whereby using concords of the class the noun belongs to (5/6 for augmentatives, 7/8 for diminutives) emphasises the diminution or augmentation.

Locative classes

A locative noun is a derived noun that indicates a location associated with the base noun from which it is derived. The change in meaning can translate to a variety of English prepositions indicating location, such as "in", "at", "on", "to" or "from", and is thus quite general in meaning, with the exact meaning of the phrase generally being determined by the verb.

The Arabic loan noun mahali "place" (and its variations: pahali, mahala and pahala) is the only noun which inherently belongs to the locative class. Other nouns can be made locative by adding the suffix -ni to the end, although this is not available for proper nouns referring to places, any animate nouns, recent loanwords and some other arbitrary nouns.

Because locative nouns constitute three classes of their own, they cannot take the usual concords of the noun they have been derived from. The concords themselves show in which one of the locative classes the noun is being used. Class 16 is marked by concords based on pa- and indicates specific location. Class 17, with concords based on ku- indicates a more general location. Class 18 has concords based on mu- and indicates internal location.

• nyumba ya Rehema "Rehema's house" (class 9)
• nyumbani kwa Rehema "at/to/from Rehema's house" (class 17)
• chumba cha Daudi "Daudi's room" (class 7)
• chumbani mwa Daudi "in/into/out of Daudi's room" (class 18)

Apposition and compounding

The equivalent of compound words is usually formed using the genitive construction such as mpira wa kikapu "basketball" (literally "ball of basket"). This is similar to the compounding process found in many languages such as French fin de semaine "weekend" (literally "end of week").

There are also many compounds which do not use the genitive preposition -a. In these cases, two (or more) nouns are simply placed side by side. This is the case of skilled workpersons such as fundi viatu (shoemaker), fundi baskeli (bicycle mechanics) and so on.

The word order is the reverse of most compounds in English, with the head always preceding the modifiers in Swahili; in other words, the first noun describes what it is, and any subsequent noun narrows or specifies that description. For example, the class 9/10 noun punda "donkey(s)" is followed by the class 4 noun milia "stripes" to mean "zebra". Whereas in English, a hypothetical equivalent compound would place the noun for the stripes first and also require the singular: "stripe-donkey", the word for "donkey" appears first in Swahili.

There is a good deal of variation among different authors as to whether the nouns are written together, hyphenated or separated and thus the word for "zebra(s)" may appear as any of pundamilia, punda-milia or punda milia.

A few common compound words have irregular plural forms because number marking occurs on both elements. The word mwanamke "woman" becomes wanawake "women" in plural. Similarly, mwanamume "man" becomes wanaume "men" in plural, although the singular form mwanaume is also common. These two nouns are formed from the word mwana "son, daughter", which is commonly used in compounds to essentially mean "person", followed by the words mke "wife" (plural: wake) and mume "husband" (plural: waume) respectively.

Pronouns

Pronouns behave in many ways like nouns, having both plural and singular forms, being present in the full range of noun classes but no inflection for case, meaning that, for instance, there is no difference between we and us, which are both sisi.

Personal pronouns

Personal pronouns occur in two forms: an independent form, which is used as a word alone, and a combining stem, which is used when combined with words such as na "with, and" and ndi- "it is". The independent form consists, in all cases except for wao, of a reduplication of a syllable. Nyinyi, however, may alternatively be dissimilated to ninyi. These pronouns also have a separate genitive (possessive) stem, which is the combining stem that is used when a genitive prefix is added.

Note that the sex/gender of referents is not distinguished, with yeye capable of meaning either "he" or "she". These pronouns are, however, restricted to use with animate referents, i.e. people or animals, so it does not generally mean it. The genitive form -ake has no such restriction and may mean "his", "hers" or "its" depending on context.

The genitive (or possessive) forms are given prefixes corresponding to the class of the possessed noun which precedes it as shown in the table in the section on the genitive -a, for example kitabu changu "my book", vitabu vyangu "my books", jina lako "your name", majina yao "their names".

Swahili is a pro-drop language. As the verb usually already includes prefixes to indicate the subject and object, personal pronouns are not strictly needed, and are mostly used for emphasis. The exceptions to this include cases when the copula ni (or its negative counterpart si) is used, as well as with the habitual form of the verb, which lacks subject prefixes.

In informal speech, when pronouns are unstressed, they may appear in a reduced form, such as mi or mie for mimi, we or wee for wewe etc. This mainly occurs when the pronoun is not added only for emphasis, but is needed (e.g. mi ni "I am", informally), and this also frequently occurs where the first person singular subject prefix ni- is dropped in casual speech before -na-. For example, standard (mimi) ninajua "I know" often occurs as (mi) najua in spoken Swahili.

Reference and relative pronouns

Each noun class has a corresponding reference pronoun (or combining pronoun) which is a single syllable that never stands alone but may be suffixed on certain other words such as na and ndi- where it can be thought of as meaning "it" (singular classes), "they", "them" (plural classes) or "here", "there" etc. for the locative classes. For all noun classes other than class 1, the reference pronoun is formed by suffixing -o to the verbal concord with sound changes such as the disappearance of u and a, the transformation of i to y when alone or preceded by v, the palatalisation of ki to ch etc.

The reference pronouns are added to specific slots in relative verb forms and thus may be glossed as either REL "relative" or REF "reference". The independent relative pronouns, equivalent to English relative pronouns (that, which, who(m)) and relative adverbs (where, when, how) are formed by attaching the reference pronouns to amba-.

Determiners

Determiners in Swahili are capable of being used adjectivally (with a noun) or pronominally (standing in for an absent noun). The inflection of Swahili determiners resembles that of verbs.

Articles

There are no articles in Swahili. A word such as kitabu "book" may be taken to mean either "the book" or "a book" depending on context.

If a distinction must be made, demonstratives or adjectives may be used to provide various shades of meaning such as kitabu hicho "that (aforementioned) book", kitabu kimoja "one book", kitabu fulani "some (particular) book", kitabu chochote "any book (at all)".

A verbal object prefix may also be used in conjunction with a nominal object and this is more frequent when a definite reading is preferred.

• Nitaleta kikombe kesho. "I will bring a cup tomorrow."
• Nitakileta kikombe kesho "I will bring the cup tomorrow."

An effect similar to a definite article may be achieved by the use of a medial demonstrative (before or after the noun) or a distal demonstrative (placed before the noun or before any following adjectives). These are not quite equivalent to demonstrative articles in languages where article use is obligatory as these demonstratives merely serve to highlight that the referent has already been mentioned and are thus a little more emphatic than a true definite article.^[3]

• Nita(ki)leta hicho kikombe kesho. "I will bring the/that (aforementioned) cup tomorrow."
• Nita(ki)leta kikombe hicho kesho. "I will bring the/that (aforementioned) cup tomorrow."
• Nita(ki)leta kile kikombe kesho "I will bring the/that (aforementioned) cup tomorrow."

Demonstratives

The demonstratives in Swahili may be used either as adjectives, with a noun, or as pronouns, standing alone. They occur in three types:

• Proximal ("this, these"), referring to something near the speaker. It is formed by prefixing the verbal concord with hV- where "V" stands for a vowel identical to the vowel of the next syllable.
• Distal ("that, those"), referring to something far from both speaker and listener. It is formed by suffixing -le to the verbal concord.
• Medial/Referential ("the aforementioned"), referring to something that has been previously mentioned. It may also occasionally be used to refer to something nearer to the listener than the speaker. It is formed by replacing the final syllable of the proximal demonstrative with the appropriate reference pronoun for the noun class.

The demonstratives may stand alone, as pronouns, but may also be used adjectivally in combination with a noun, much like "this" and "that" in English. The demonstrative generally follows the noun but it can also precede it for emphasis. Before a noun, it often takes on a slightly more article-like role, as explained above.

Other determiners

The words -ote "all", -o-ote "any", -pi "which" and -enyewe "-self", "-selves", appear with prefixes following the verbal inflection pattern. In older texts, -o-ote was frequently written as two words (e.g. yo yote, vyo vyote) however it is now more frequently written together. For the sake of comparison, the following table also includes the genitive and ornative prepositions -a and -enye as well as the verbal subject prefixes for each class. Note that class 1 has the most irregularity and diversity of form.

1. The 1st and 2nd person plural have their own forms for "all", namely sote and nyote. These may be used with or without the pronoun: sisi sote or simply sote can mean "all of us", "we all". When used with the form wote, the meaning is "both": sisi wote "both of us", "we both".
2. The irregular form wepi is used to avoid clashes with the word wapi meaning "where".
3. The word vipi may be used to ask "which" of class 8 nouns (e.g. vitabu vipi? "which books?"), but, as is typical for class 8, can also be understood adverbially, following a verb to mean "how?".
4. The usual word for "where" or "which place" is wapi, however some sources list a regular form papi.

Adjectives

The term "adjective", as applied to Swahili and most other Bantu languages, usually applies only to a rather restricted set of words. However, in the wider sense, it can refer to any word that modifies a noun. The wider sense is used here. Adjectives in the stricter Bantu sense are referred to as "true adjectives" in this article. True adjectives in Swahili may be divided into two categories: inflecting adjectives, which take a prefix indicating the noun class of their referent, and invariable adjectives, which do not take a prefix.

All adjectives have one thing in common: they all follow the noun they modify, and, aside from the plain adjectives, require some kind of prefix whose class matches the preceding noun. The different types of adjectives reflect the different prefixes that are used:

• Inflecting adjectives are true adjectives which are prefixed with an adjective concord.
• Plain adjectives are true adjectives which do not take concord prefixes.
• Relatives are relativised verbs which can be used as adjectives.
• Genitives are phrases consisting of a noun introduced by the genitive preposition -a.
• Ornatives are phrases consisting of a noun introduced by the ornative preposition -enye.

Inflecting Adjectives

Inflecting adjectives are words which describe a noun or pronoun and take the following prefixes, which are very similar to the prefixes found on nouns. This distinguishes them from determiners, which take prefixes similar to those on verbs. The most notable departure from the nominal inflection pattern among inflecting adjectives is the replacement of the nominal u- prefix in class 11 (and generally also 14) with the adjectival m- prefix. The locative classes also carry prefixes, unlike the locative nouns they refer to.

Most inflecting adjectives have stems beginning with a consonant. Of those that begin with a vowel, almost all of these have stems that begin with either e (for example, -ekundu "red") or i (e.g. -ingi "many, much"). A very small minority of adjectives begin with other vowels, but these happen to refer only to animate referents and thus only have forms in classes 1 and 2, for example: -ovu "evil, wicked", which is mwovu in class 1 and waovu in class 2.

1. The ji- prefix only occurs on the adjective -pya "new" in order to make sure it has more than one syllable so that the antepenult can be stressed.
2. The N- prefix in classes 9 and 10 exhibits considerable variation. On adjectives with stems of more than one syllable, it only appears as a prenasalisation of the following consonants: b → mb, d → nd, g → ng, j → nj, l → nd, r → nd, v → mv, w → mb, z → nz. Elsewhere, it disappears. In addition, the monosyllabic adjective stem -pya "new" has the form mpya, whereby the m- constitutes the stressed syllable.
3. The adjective -ema "good, kind, nice" has the irregular form njema in class 9 and 10 instead of the expected form *nyema.
4. In modern standard Swahili, adjectives in class 14 take the prefix m(w)-, however, in an earlier stage of the language, they took the prefix u-/w- which is still preserved in some idiomatic phrases but has otherwise disappeared, marking the almost complete merge of classes 11 and 14.

The adjective -ingine "other", is sometimes given inflections prefixes of the type found with determiners, following a verbal rather than a nominal pattern. Most notably, the forms lingine in class 5, ingine or yingine in class 9 and zingine in class 10 may be heard. Some speakers also use an e in these classes: jengine, lengine, nyengine, yengine and zengine sometimes occurring. These forms are regarded as non-standard, although they may be commonly heard. The standard forms of each are jingine for class 5 and nyingine for classes 9 and 10.^[7][8]

The numerals -moja "one", -wili "two", -tatu "three", -nne "four", -tano "five" and -nane "eight", as well as all numbers that end with these words, take prefixes as inflecting adjectives do.

• mtu mmoja "one person", watu wawili "two people", watu ishirini na mmoja "twenty-one people", watu ishirini na wawili "twenty-two people"
• kitabu kimoja "one book", vitabu viwili "two books", vitabu ishirini na kimoja "twenty-one books", vitabu ishirini na viwili "twenty-two books"
• nyumba moja "one house", nyumba mbili "two houses", nyumba ishirini na moja "twenty-one houses", nyumba ishirini na mbili "twenty-two houses"

Invariable adjectives

Invariable adjectives are mostly loanwords from Arabic, such as safi "clean", ghali "expensive", although loanwords from other languages are also present, such as faini, from English "fine". Nouns placed as modifiers after other nouns may also be regarded as invariable adjectives, such as msichana kiziwi "Deaf girl", which has a class 1 prefix m- and a class 7 prefix ki-. Numbers loaned from Arabic: sita "six", saba "seven" and tisa "nine", ishirini "twenty", etc., as well as the native Bantu number kumi "ten", function as invariable adjectives. The interrogative adjective gani "what kind of" or, colloquially, "which" is also invariable.

• watu tisa "nine people"
• vitabu tisa "nine books"
• nyumba tisa "nine houses"

Relatives

Relatives are verbs used as adjectives by being relativised using a relative prefix (or suffix) which agrees with the noun's class. In the following table, all forms given have a subject prefix and a relative affix that correspond to the same noun class as this is always the case when verbs are used in this simple adjectival manner. More complex relative clauses, which will not be further discussed in this section, frequently involve different noun classes.

These are frequently used in Swahili and make up for the relative paucity of true adjectives. For example, there is no true adjectives equivalent to the English adjective "open". The verb kufunguliwa "to be opened", when relativised, conveys this meanings. Examples of this in use:

• mlango uliofunguliwa "open door" (door which was opened)
• milango iliyofunguliwa "open doors" (doors which were opened)
• dirisha lililofunguliwa "open window" (window which was opened)
• madirisha yaliyofunguliwa "open windows" (windows which were opened)

Similarly, although the adjective -fu "dead", "deceased" exists, it is comparatively infrequently used, its meaning often instead being expressed through a relativisation of the verb kufa "to die". Examples.

• ndege aliyekufa "dead bird" (bird which died, c.f. ndege mfu)
• ndege waliokufa "dead birds" (birds which died, c.f. ndege wafu)

Relativised verbs are frequently used in phrases describing time:

• wiki iliyopita "last week" (week which passed)
• wiki mbili zilizopita "two weeks ago (two weeks which passed)
• wiki ijayo "next week" (week which comes, coming week)
• wiki tatu zijazo "in three weeks" (three weeks which come, three coming weeks)
• mwaka uliopita "last year" (year which passed)
• miaka minne iliyopita "four years ago" (four years which passed)
• mwaka ujao "next year" (year which comes, coming year)
• miaka miwili ijayo "in two years" (two years which come, two coming years)

Genitive adjectives

Another construction which makes up for the paucity of true adjectives in Swahili is the genitive construction using the genitive preposition -a. The prefixes that this preposition takes are outlined here.

In many cases, the noun introduced in a genitive adjective phrase receives an additional ki- prefix, such as -a kimataifa "international" (from mataifa "nations") and -a kihistoria "historic" (from historia "history").

Ornative construction

Yet another construction which makes up for the paucity of true adjectives in Swahili is the ornative construction using -enye. Some examples of adjectival phrases with -enye include -enye nguvu "strong" (with strength), -enye nywele fupi "short-haired" (having short hair), and -enye senta moja "concentric" (having one centre). The forms of -enye as well as some more examples of use can be seen here.

Verbs

Like nouns, verbs are formed by adding prefixes to a basic stem. However, unlike the prefixes of nouns, verbal prefixes are not a fixed part of the verb, but indicate subject, object, tense, aspect, mood and other inflectional categories. Normally, verbs are cited in dictionaries in the stem form, often with a hyphen to indicate that prefixes are added, such as -sema "say", -andika "write", -la "eat". It is also possible to use the infinitive/gerund form which begins with ku- or, for a couple of verbs only, kw-, such as kusema "to say", kuandika "to write", kula "to eat".

Overview of verb structure

Prefixes are always attached in a fixed order; the object prefix always comes last, immediately before the verb stem, while the subject prefix comes before the object prefix. Most of the time, a tense, aspect, mood or polarity prefix may intervene between the subject and object prefix, or be placed before the subject prefix. A common mnemonic used by learners of Swahili for the order of parts of a verb is STROVE.

• Subject prefix
• TAM prefix (or usually Tense prefix)
• Relative prefix
• Object prefix
• Verb stem
• Extension(s) (meaning "derivative suffix(es)"), or, more broadly Ending (including also the inflectional suffixes -i and -e).

In learner materials, all types of prefixes other than the subject prefixes are frequently referred to with the dated term "infix". The term infix, as used by linguists, would refer only to an affix that was inserted within the verbal root, not between the verbal root and another prefix, or between two other prefixes. Under the modern definition of the word, Swahili does not have infixes.

Here is an example of a verb with all slots filled:

* This "(a)" appears when this is the final element of the word and is otherwise dropped.

Most of the time, verbs will not have all slots filled. Here are some other examples.

There are a number of derivational suffixes (frequently termed 'extensions') which can be added to the end of verbs to derive new meanings, some of which have been shown above.

Inflection groups

There are three basic inflection groups which differ only very slightly from one another:

1. common verbs
2. short verbs
3. loan verbs

Common verbs are the largest group of verbs in Swahili. In their infinitive form, they consist of three or more syllables and end with -a. All verbs of native Bantu origin end with -a, including the short verbs mentioned below. Some examples of common verbs are kuanguka "to fall", kufanya "to do, to make", kuona "to see", kuwaza "to think", kusaidia "to help". The final -a is replaced with another vowel in certain grammatical contexts, becoming -i in the present negative, and -e in the subjunctive and imperative forms involving an object prefix. The plural address marker -ni also triggers this final -a to become -e.

Short verbs are those which, in their infinitive form, consist of only two syllables, such as kula "to eat", kunywa "to drink", kuja "to come", kupa "to give". The verbs kwenda "to go" and kwisha "to finish" may belong to this group, although it is also common for these verbs to be conjugated as common verbs (as kuenda and kuisha). Because the stems of most of these verbs, once the infinitive prefix ku- is removed, are monosyllabic, these are frequently termed monosyllabic verbs, however this is problematic as the final -a of Bantu verbs is often not considered to be part of the root (meaning that roots of many of these verbs consists of only a single consonant or consonant cluster, such as -p- "give"). Furthermore, when the final -a is considered part of the stem, this excludes -enda and -isha, which generally conjugate in a similar way to the other short verbs. The short verbs are all native Bantu verbs ending in -a and undergo the same -i and -e alterations as the common verbs. Additionally, they are characterised by the insertion (or retention) of the syllable -ku- in certain verb forms. This intrusive -ku- (which may be glossed as EXT for "extension") prevents the penultimate stress from falling on certain TAM prefixes (-na-, -me-, -li-, -ta-, -sha-, -nge-, -ngeli-) and relative prefixes, which are inherently unable to be stressed. This -ku- disappears in verb forms where the stress is allowed to fall on a subject or object prefix, or on certain other TAM prefixes (-a-, hu-, -ki-, -ka-, -ku-, -si-). (The TAM prefix -ja- can be regarded as belonging to either group, depending on the speaker.) Because the initial stem vowel of -enda and -isha takes the stress, this explanation does not sufficiently fit, however it should suffice to say that the distribution of their -kw- extension, among speakers who use it, is identical to that of the -ku- extension in other short verbs.

The Loan verbs, also frequently called "Arabic" verbs, are those which do not end in -a in the infinitive. Not all verbs from Arabic are in this group, however, such as kusaidia, which is an Arabic loan which happens to end in -a and is thus conjugated as a common verb. Likewise, not all Loan verbs come from Arabic, such as kukisi "to kiss" and kuripoti "to report", which are from English. What these verbs share in common is that they are all loan-words and none of them end in -a. The consequence of this is that they do not take the suffixes -e and -i that the verbs ending in -a do, which occasionally results in ambiguity, such as in si-ku-sahau-Ø which could either mean "I did not forget" (NEG.1S-NEG.PST-forget-Ø) or "I do not forget you" (NEG.1s–2s-forget-PRES.NEG).

Subject and object concords

Both the subject and, when applicable, the object of the verb are indicated by prefixes or concords attached to the verb stem. Swahili is a pro-drop language: explicit personal pronouns are only used for emphasis, or with verb forms that do not indicate subject or object. When a noun is used as the subject or object, then the concord must match its class. Animate nouns (referring to a person or animal) are an exception and these occur with concords of the noun classes 1 (singular) or 2 (plural). The subject concord must always be present, except in the infinitive, habitual and imperative forms. The object concord is generally optional; although some sources maintain that it must always be used with animate objects, this appears not to be the case as counter-examples are commonplace. Whether it is used or not appears to have to do with animacy, specificity and definiteness as well as pragmatic considerations of emphasis.

Six different forms of verbal concord exist.

For the subject, there are both negative and positive forms, while there are only positive forms for objects. The negative subject concords are formed by prefixing the syllable ha- to the beginning, except for the irregular forms si- (instead of *hani-), hu- (instead of *hau-) and ha- (instead of *haa-) which are used, respectively, for first, second and third person singular animate subjects.

Additionally, in (the third person singular of) noun class 1, the prefix yu- is used instead of a- as the subject of a locative copula. (This yu- can also be seen in the demonstratives.) The negative form of yu- is formed regularly, by appending the prefix ha-.

Before the present 'indefinite' marker -a-, subject concords are shortened to just a consonant or consonant cluster in a similar manner to the prefix which occur on the genitive preposition -a.

Object concords are generally the same as the positive subject concord, although there are a few exceptions for instances involving animate referents; 2nd person singular and plural, as well as 3rd person singular (class 1) all have different forms for subject and object concord.

Examples:

• Tunakwenda sasa. "We are going now."
• Sisi tunakwenda sasa. "We are going now." (with emphasis)
• Ninamwona. "I see him/her."
• Ninamwona yeye. "I see him/her." (with emphasis)
• Ninampa zawadi. "I give him/her a gift."

Because the 2nd person plural object prefix -wa- is the same as the object prefix for class 2 (3rd person plural object), a word such as ninawaona may ambiguously mean "I see you all" or "I see them." These two possibilities may be disambiguated by placing the pronoun after the verb: ninawaona ninyi / wao. Very frequently, however, the suffix -eni is appended to the verb to indicate that the second person plural is meant: ninawaoneni "I see you all." This suffix causes the final a of Bantu verbs to shift to e. On loan verbs, this suffix is simply -ni. Some speakers use the prefix -ku- (otherwise indicating 2nd person singular) with the suffix -(e)ni, as in ninakuoneni "I see you all."

The reflexive prefix only occurs as an object, and refers back to the subject of the sentence. It is equivalent to English forms like myself, yourself, himself and so on.

• ninajitetea "I defend myself"
• anajiona "he sees himself" (idiomatically, may mean: "he is conceited")

Infinitive

The infinitive is a verbal noun, and belongs to the nominal class 15, which is reserved specifically for infinitives. It is marked by the prefix ku-. It may occur in the same contexts as other nouns and may, occasionally, even be derived into the locative classes by means of attaching the suffix -ni, as in kuangukani "in falling" (i.e. "while falling"). It corresponds to the English infinitive or gerund. Infinitives cannot take subject, relative or TAM prefixes, but they may take object prefixes.

The negative infinitive is derived from the verb kutoa "to subtract", "to not do", although it is rarely encountered in its full form for this use. The additional -ku- in brackets is the infinitive marker of the original verb, although it may be omitted as long as stress rules allow.

Tenses, aspects and moods

For the sake of simplicity, the following verb forms may be referred to as "tenses" as they often are in learner materials, but many of these are not grammatical tenses in the technical sense but may instead be aspects or moods. All together, Tense, Aspect and Mood may be abbreviated as TAM.

The following table shows a summary of TAM forms which will be discussed in further depth below. Brackets indicate optional elements and slashes indicate alternative elements of which either (but not both) may fill the same slot in the verb. The column labelled 'final vowel' is only relevant for "short" and "common verbs", with "loan verbs" remaining invariable here with the exception of the -ni suffix added to indicate 2nd person plural address. In any TAM form, when the object is 2nd person plural, this -(e)ni prefix may also occur, but this is not shown in this table.

* Note that the 'indefinite' present -a- causes the form of the subject marker to change as outlined above.

Imperative

The imperative mood is used to issue direct commands. It can occur either alone or with an object prefix. The presence of an object prefix (including the reflexive ji-) causes the final -a of Bantu verbs to become -e. Note that the ji- prefix of reflexive verbs is an object prefix, meaning, for example, that the imperative of -jifunza "to learn" is jifunze "learn!" and not *jifunza.

The plural form, with the suffix -ni, is used when addressing multiple people.

The following verbs have irregular imperatives, regular forms may be heard, particularly by non-native speakers and particularly in Kenya, and regular forms may be interpreted as less polite:

• kuja "to come": njoo (pl. njooni)
• kwenda "to go" : nenda (pl. nendeni)
• kuleta "to bring": lete (pl. leteni)

The verb -acha may informally be given the imperative form wacha (pl. wacheni).

Additionally, the verb kuwa "to be" has an irregular imperative form: iwe (pl. iweni), although this is rarely used and more frequently replaced by a regular imperative form kuwa (pl. kuweni) or used in the subjunctive ("polite imperative") form: uwe (pl. mwe).^[9]

There is no actual negative imperative form. The equivalent is achieved with the negative subjunctive (as in Spanish). The formation of this is outlined below, but for the sake of completeness the negative equivalents of the above examples are given here.

The suffix -ni is used when the order is addressed to each of the people. When an order is given to any of the addressed persons the subjunctive mood is used.

For instance when a load is meant to be carried, if it is heavy and all the people should help, Bebeni mzigo. When anyone could help carrying on their own Mbebe mzigo. When introducing people in a waiting room, Mkae hapa implies that all the people will be called together. Kaeni hapa implies that anyone could sit and they will be called one by one. The suffix -ni is thus the locative suffix which specifies that the order is given to everyone, distinctly in the time-space.

Present tenses

There are two present tenses in Swahili. These are sometimes termed the "definite present" (with -na-) and the "indefinite present" (with -a-). In modern, standard Swahili, however, there is no great difference in meaning between these two forms as the "indefinite present" is more or less obsolete and rarely used other than its frequent appearance in media headlines.^[10] A distinction between these two forms is not made in the negative, with both forms being negated the same way.

* Although rarely used, the "indefinite present" adds a small complication to the presentation of Swahili grammar as the -a- marking the tense causes the subject concords to undergo reduction in the same manner as the prefixes of the genitive preposition -a. This is outlined above.

In informal Swahili, it is very common for the first person singular concord ni- to collapse into the -na- of the definite present tense marker and become inaudible (and unwritten). The distinction between the "definite" and "indefinite" present tense forms appears to vanish in the first person as both begin with a na-, however short verbs retain their -ku- extension in the -na- tense and lose it in the -a- tense, allowing this distinction to still be felt, such as in (ni)nakula "I eat", in the -na- present tense, versus nala "I eat", in the -a- present tense.

Habitual

The habitual verb form is unusual in that it does not allow subject prefixes to appear on it. The prefix hu- is added to the beginning of the verb and short verbs do not need their -ku- extension.

The habitual indicates repeated, habitual occurrence of an action (habitual aspect) or something occurring as a timeless general rule (gnomic aspect). Because subject prefixes are absent, personal pronouns are very frequently used to indicate the subject.

The habitual aspect with hu- is often replaced by the present with -na- in everyday use, the sisi hunywa of the above example then being replaced with tunakunywa. In order to maintain the habitual meaning, the word huwa (the habitual form of kuwa "to be") may precede the verb, such as Huwa tunakunywa. This may be regarded as an example of a compound tense, however because of the invariability of huwa, it may also be regarded simply as an adverb with the meaning "habitually".

In the informal speech of some regions, speakers instead make frequent use of the non-standard habitual suffix -ga or -nga, which has entered Swahili from other Bantu languages spoken in East Africa, giving forms such as tunakunywaga or tunakunywanga for "we habitually drink". These suffixes mean either the performance of an action as a habit or that it occurs "once in a while", as these examples show:

• Umewahi kwenda Morogoro? "Have you ever been to Morogoro?"

→ Naendaga "Yeah, I go there (habitually/from time to time).

• Wee unacheza ngoma? "You do you dance to traditional music?" (Wee is an informal form of wewe.)

→ Nachezaga "Yeah, I do."

→ Sichezagi "No, I don't."

Although there are many ways in which the habitual aspect with hu- is avoided in informal speech, it is, however, very commonly used in proverbs dealing with eternal truisms.

In generalisations about the habits of groups of people, speakers often synecdochically pair a singular subject with a verb taking the hu- prefix. Mtanzania hulala uchi "A Tanzanian sleeps naked." ("Tanzanians sleep naked.") Informally, however, the present tense with -na- may be used in this way as well: Mfaransa anakula chura, "A French person eats frogs." ("French people eat frogs.") Pointing out an eagle hovering above a hamlet, Yule mtu anakula kuku, "That type of guy eats chicken."

Past

The past tense is used in Swahili to talk about actions or states in the past, whether in the near or the distant past. It is formed with the prefix -li-. Its negative equivalent is formed with the negative subject prefix plus -ku-. The positive tense marker -li- cannot take stress and triggers the use of the extension -ku- (or -kw-) where necessary. The negative tense marker -ku- can take stress, meaning that an additional -ku- extension is not needed.

Perfect

The perfect indicates an action or situation which occurred in the past, similarly to the past tense, however the focus of the utterance is on the relevance of this past action to the present moment. For example, the word nimepika "I have cooked" describes a past action with present relevance (i.e. the food is ready now) whereas nilipika "I cooked" describes a past action with no implication of any relevance to the present (the food may have been eaten long ago, or not).

The perfect is formed in the positive with the prefix -me-. The negative is formed with the negative subject prefix plus -ja-. As with the present and past tenses, the positive present marker -me- cannot take the word stress and triggers the appearance of the -ku- extension in short verbs, but the negative marker -ja- is able to be stressed. Some speakers may use the extension -ku- with -ja-.

Some sources describe the -ja- form as containing more of an implication of "not yet" than a simple negation of the -me- form, however the word bado "still", "not yet" may be used to indicate this explicitly where necessary.

Inchoative verbs, such as kuchoka "to get tired", which describe the entering of a state, are used in the perfect to indicate being in the state in question. Compare for example: ninachoka "I am becoming tired"; nimechoka "I have become tired", i.e. "I am tired." For more information and examples, see the section on inchoative verbs below.

Some speakers may replace the sequence of prefixes a-me- with ka- with more or less the same meaning. This may derive from the consecutive tense marker.^[11]

Anterior -sha-

The anterior marker -sha- (or sometimes -kwisha-) is a relatively new TAM marker that derives diachronically from the verb kwisha "to finish, to run out". It is most commonly (and perhaps least controversially) used directly after the perfect marker -me-. It often imparts the meaning of "already", emphasising the completeness of the action.

The anterior marker -sha- is also used with other TAM markers, simply sitting after them within the TAM slot. It may also on occasion be used on its own, with a function more or less equivalent to the perfect -me-. These uses may not be regarded as standard Swahili. It is frequently used with the situational marker -ki- where it indicates a situation in which the action has been completed.

Future

The future tense is formed in Swahili with the prefix -ta-. The negative form is indicated simply by using the negative subject prefix, with -ta- being used here as well. A number of speakers, however, use -to- in the negative future. This may be derived by analogy from the -to- of the negative infinitive, and may also disambiguate between positive and negative where the only difference otherwise would be an h- at the beginning of the negative word. For example, atakuja "s/he will come" vs. hatakuja "s/he will not come" (or hatokuja). Because second language speakers in many areas have trouble with pronouncing and distinguishing /h/, the optional change from -ta- to -to- in the negative can provide a failsafe indication when a negative meaning is intended.

-Ta- (and likewise -to-) cannot take the word stress whether in positive or negative and thus causes the appearance of the -ku- extension in short verbs.

Subjunctive

The subjunctive (sometimes referred to as an optative) expresses hypothetical situations, wishes and requests. It is also used as a complement to certain auxiliary verbs and conjunctions. The subjunctive is indicated by the lack of any Tense-Aspect-Mood prefix and the change of the final -a, where present, to -e-. The class of loan verbs, which do not end in -a, do not undergo this change and the subjunctive form is made by simply omitting any tense marker. The negative subjunctive is indicated by adding the syllable -si- into the tense slot, with the positive subject prefix being used rather than the negative.

The subjunctive is frequently used following the equivalents of modal verbs, verbs indicating wishes, suggestions, recommendations and other constructions.

The verb kutaka and such verbs expressing wishes or intentions like kutegemea to intend are usually followed by the subjunctive even when the subject is the same in both propositions; Nataka niende sokoni I want to go to the market. Mtoto alipewa kitabu asome The child was given a book so that he could study. Sisi tunategemea tuende picha usiku We've planned to go to the theatre (movies) tonight. It applies when there a possibility of influencing the factors encountered in the context. If there is nothing to do about the context then the infinitive is used.

Wale watu wanataka kutawala dunia Those people want to rule the world.

Nataka kukojoa I want to piss

Anataka kufa He wants to die (He's going to die)

Wale wageni wanataka kuondoka The guests want to leave

Compare with: Nataka nikojolee chooni I want to piss in the toilet. Walitaka waondoke mapema They wanted to leave early (and they didn't wake up) Walitaka kuondoka mapema They wanted to leave early (and the road was flooded)

An equivalent of "must" or "have to" is formed with ni lazima "it is necessary", or simply lazima "necessarily" followed by the subjunctive.

The subjunctive may be used on its own with a second person subject as a more polite alternative to an imperative. As there is no negative imperative, forms beginning with usi- and msi- may also be interpreted as such.

Situational

The situational, simultaneous or conditional tense is formed with the TAM prefix -ki-. This prefix may take stress and thus the extension -ku- does not appear with short verbs in the situational verb form.

There is, strictly speaking, no negative form of the situational, however, in conditional sentences, the relative verb form using -sipo- is quite close in meaning to a negative equivalent of -ki- and it will be given here as it may prove helpful. Note that the -ku- extension does appear with -sipo- as the -po-, like all relative syllables, is unable to be stressed.

The situational verb form is used to indicate a simultaneous action or situation of subordinate importance that provides the temporal or contextual background for the main verb in the sentence. It is somewhat equivalent to the English conjunctions "if" and "when", but it also forms the equivalent of adverbial participle clauses. If needed for clarity or emphasis, a word meaning if, such as kama, ikiwa or endapo may be added to the beginning of the clause (which allows the speaker to choose a different TAM marker). The word ikiwa is itself the situational form of the verb -wa "to be", with the class 9 subject prefix i-, literally meaning on its own essentially "if it is".

The situational may appear in compound progressive tenses.

Consecutive

The consecutive or narrative tense is formed with the TAM prefix -ka-. This prefix may take stress and thus the extension -ku- does not appear with short verbs in this form.

The consecutive tense is mainly used with the past tense -li- in narrating a sequence of events whereby -li- is used for the first verb and -ka- for subsequent verbs. It roughly carries the meaning "and then" and makes the use of na "and" or halafu / kisha "then" essentially redundant. Where context is clearly past, a narrative may also be begun with -ka-.

There is, strictly speaking, no negative form of the consecutive, however the negative subjunctive may occasionally be used for this purpose.^[12]

Expeditous

The consecutive marker -ka- may combine with the final -e of the subjunctive mood to form the expeditous.

The expeditous verb form is essentially the same as the subjunctive in meaning except with the added meaning of "and" or "then" introduced by the consecutive marker -ka-.

The word akawe in the above sentence could also be replaced with ili awe "in order that he be" or simply the subjunctive awe "that he be" (or "(for him) to be" in more natural contemporary English), but the -ka- added to this word emphasises his becoming an ambassador immediately following his being dispatched.

The expeditous verb form is frequently used with imperatives (and "polite imperatives" in the subjunctive), again indicating roughly "and then".

The subject prefix may be dropped when used with the imperative.

Irrealis

There are two irrealis verb forms, one which may be called "present irrealis" (marked by -nge-) and one which may be called "past irrealis" (marked by -ngali-). The standard means of forming the negative is to use -si- in the TAM slot, forming -singe- and -singali-. Some speakers, however, particularly in speech influenced by southern dialects,^[13] negate the irrealis verb forms instead by using the negative subject concords.

Both the irrealis forms are used to discuss hypothetical situations, generally within conditional sentences. Both the protasis (if-clause) and apodosis (then-clause) may have an identical structure with the protasis appearing first. In order to disambiguate or emphasise, such as if the clauses are in the reverse order, a word for "if" (kama, ikiwa, endapo) may precede the protasis.

In the usage of many speakers, the distinction between the present and past irrealis forms is somewhat blurred so that the final example above may commonly be spoken as "(Kama) ningejua hiyo, nisingekuja hapa." which, speaking strictly, could be interpreted as "If I knew that I would not come here."

Relative verb forms

There are five verb templates which can be used to create relative clauses. The three simple tenses PAST, PRESENT and FUTURE may only be relativised in their positive sense. In addition to these, there is a tenseless positive form and a tenseless negative form. For all other verb forms, relative clauses must be formed by a periphrastic relative using amba-.

The following table shows the structure of the verb templates, notably the positioning of the relative morpheme, here labelled "REL". Note in the following table that the marker for the future tense is -taka- with a following relative morpheme, rather than the simple -ta- which occurs otherwise.

The relative morpheme takes one of many forms to indicate the class of its referent. The relative morpheme for each class is identical to its combining pronominal form which appears with na- and ndi-. Aside from class 1, the form of each can be achieved by placing o (the so-called "o of reference")

The tenseless relative form is used when expressing a general meaning or a habit: Wakao hapa The ones who (usually) sit here. Usiache mbachao kwa msala ujao Don't leave a rotten mat for a (nice) praying mat which may come (A bird in your hand is better that two birds in the bush). Kitabu hichi ndicho nikitafutacho This the book I look around (I've been seeking for ages). It is also used in some copula Kitabu nilicho nacho The book I am with (the book which is with me).

The tensed aspect is connected to a specific time either in the present, the future or in the past. Therefore it is used with a definite past -li- and not with the recent past -me-. The relative is the same expressing the subject (who) or the object (that, which).

Kitu kilichonipendeza The thing which pleased me

Kitu nilichokipenda The thing I liked

Chagua matunda yale yaliyoiva Choose the fruit the ones which are ripe.

Chagua yale uliyoweka pembeni Choose the ones you put aside.

"Kituo kinachofuata Faya" The next stop (which follows) is Fire.

Yule aliyekuja sasa hivi kashaondoka The one who came at the moment has gone already.

Wanaokaa hapa wazee The ones who are seated here are the Elders.

The periphrastic relative amba- was coined a hundred years ago by foreigners who did not like much the affix -o- and its nuances. It is nowadays widely spread in big cities like Dar, the north, and in the medias like the radio and the television. In many villages it is understood but not used. Amba- is followed by a suffix with the same agreements listed above.

Kiswahili ni lugha ambayo inaweza kusanya makabila Swahili is a language which can gather the tribes.

Mimi mtu ambaye anapenda utamaduni I'm a guy who likes traditional features.

Basi ambalo linachelewa sana The bus which is always late.

'To be'

In most languages with a verbal copula, the equivalent of the verb 'to be', it is this verb that exhibits the most irregularity and the most diversity of form. Swahili is no exception. Outside of the present tense, the Swahili verb -wa (infinitive kuwa) is almost entirely regular, inflecting as other short verbs do. In the present tense, however, there is a distinction made between a copular of essence versus a copula of state or location. This is similar to the distinction between ser and estar in Spanish and Portuguese, however, in Swahili, this distinction largely vanishes outside of the present tense. There are also irregular relativised forms for the present tense as well as an irregular unique continuative form.

Essence

Invariable copula

The invariable copula ni is used, in the present tense, to express that two noun phrases (the subject and complement) refer to one and the same referent:

• Mimi ni Bahati. "I am Bahati."
• Dunia ni sayari tunapoishi. "Earth is the planet we live on."

It is also used to express membership of a class (a subset relationship):

• Wao ni wanasayansi. "They are scientists."
• Jua ni nyota. "The sun is a star."
• Miti ni mimea mikubwa. "Trees are large plants."

It may also introduce an adjective or equivalent phrase describing a relatively permanent characteristic.

• Babake ni mrefu sana. "Her father is very tall."
• Mji huyu ni mdogo. "This town is small."
• Misuli yako ni kama chuma. Your muscles are like steel.

The negative form si can be used in all the same situations with a negative meaning:

• Wewe si Bahati. "You are not Bahati."
• Jua si sayari. "The sun is not a planet."
• Pomboo si wadogo. "Dolphins are not small."

Because ni and si do not provide any information about the subject, personal pronouns, usually only necessary for emphasis, frequently appear. Compare the typical use of irregular present tense with that of the entirely regular past tense where the subject prefixes make personal pronouns redundant and used only for emphasis.