Latino sine flexione
IL de A.p.I.
Interlingua sign in 1911
Pronunciation['latino 'sine 'fleksione]
Created byAcademia pro Interlingua under chairmanship of Giuseppe Peano
Setting and usageInternational auxiliary language
Early form
Latin alphabet 
SourcesBased on Latin, but influenced by ideas in other auxiliary languages
Official status
Regulated byAcademia pro Interlingua (-1945), works by Peano and ApI (eg Discussiones 1909-1915)
Language codes
ISO 639-3None (mis)
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Latino sine flexione ("Latin without inflections"), Interlingua de Academia pro Interlingua (IL de ApI) or Peano's Interlingua (abbreviated as IL) is an international auxiliary language compiled by the Academia pro Interlingua under the chairmanship of the Italian mathematician Giuseppe Peano (1858–1932) from 1887 until 1914. It is a simplified version of Latin, and retains its vocabulary. Interlingua-IL was published in the journal Revue de Mathématiques in an article of 1903 entitled De Latino Sine Flexione, Lingua Auxiliare Internationale (meaning On Latin Without Inflection, International Auxiliary Language),[2] which explained the reason for its creation. The article argued that other auxiliary languages were unnecessary, since Latin was already established as the world's international language. The article was written in classical Latin, but it gradually dropped its inflections until there were none.

Language codes ISO 639: ISO 639-2 and -1 were requested on 23 July 2017 at the Library of Congress (proposed: IL and ILA); ISO-639-3 was requested on 10 August 2017 at SIL (proposed: ILC) and was rejected on 23 January 2018.[3]


In 1903, Peano published the article De Latino Sine Flexione to introduce his language.[2] In this work, Peano quoted a series of suggestions by Leibniz about a simplified form of Latin.[4][5] The article appeared to be a serious development of the idea, and Peano subsequently gained a reputation among the auxiliary language movement.

In 1904, Peano undertook an essay about the way to obtain the minimal grammar of an eventual minimal Latin (Latino minimo), with a minimal vocabulary purely international.[6]

Peano and some colleagues published articles in Latino sine flexione for several years at the Revue de Mathématiques. Because of his desire to prove that this was indeed an international language, Peano boldly published the final edition of his famous Formulario mathematico in Latino sine flexione. However, as Hubert Kennedy notes, most mathematicians were put off by the artificial appearance of the language, and made no attempt to read it.[7]

In October 1907, Peano was at the Collège de France in Paris to take part in the Delegation for the Adoption of an International Auxiliary Language. Having declared for Latino sine flexione to be adopted, he eventually could not participate in the final voting, because of labour affairs at Turin.[8]

On 26 December 1908, Peano was elected member and director of the Akademi internasional de lingu universal still using Idiom Neutral, which was refounded one year later under the name Academia pro Interlingua. Every academician might use their favourite form of Interlingua, the term being initially used in a general sense as a synonym for international language, yet it soon began to be specially used to denote a reformed Latino sine flexione based on the common rules the academicians were reaching by frequent votings. Thus, the name Interlingua soon began to denote the language evolving from the Academia Pro Interlingua,[7] with the corresponding abbreviation IL.

However, every member was free to write in their own personal style, and indeed some members were proposing radical reforms which eventually might end up as independent languages (like Michaux's Romanal or De Wahl's Interlingue). For this reason, the name Peano's Interlingua or Interlingua (IL)[7] might be regarded as the most accurate for the particular standard by Peano. (As found in "Interglossa and its predecessors".[9])

The discussions to reach a standard Interlingua may be seen on the pages of Discussiones, the official journal of the Academia pro Interlingua from 1909 to 1913. This and subsequent journals of the academy have been recently published in a CD-Rom by the mathematics department of the University of Turin,[10] the place where Peano developed his teaching and research.

Since De Latino Sine Flexione had set the principle to take Latin nouns either in the ablative or nominative form (nomen was preferred to nomine), in 1909 Peano published a vocabulary in order to assist in selecting the proper form of every noun,[11] yet an essential value of Peano's Interlingua was that the lexicon might be found straightforward in any Latin dictionary (by getting the thematic vowel of the stem from the genitive ending, that is: -a -o -e -u -e from -ae -i -is -us -ei). Finally, a large vocabulary with 14,000 words was published in 1915.[12]

A reformed Interlingua was presented in 1951 by Alexander Gode as the last director of the International Auxiliary Language Association. It was claimed to be independent from Peano's Interlingua, because it had developed a new method to detect the most recent common prototypes. But that method usually leads to the Latin ablative, so most vocabulary of Peano's Interlingua would be kept. Accordingly, the very name Interlingua was kept, yet a distinct abbreviation was adopted: IA instead of IL.

Alphabet and pronunciation

Interlingua alphabet and digraphs, with typical pronunciations
Upper case A Ae B C Ch D E F G H I J K L M N O Oe P Ph Qu R Rh S T Th U V W X Y Z
Lower case a ae b c ch d e f g h i j k l m n o oe p ph qu r rh s t th u v w x y z
Distinct pronunciations (IPA) a ai̯ b, p k d e f ɡ h i j k l m n o oi̯ p r s t u w w ks y z
Merged pronunciations e k - e p, f t v v i

According to Peano's guide to the language in 1931, "most Interlinguists are in favour of the old Latin pronunciation." This gives the pronunciation of vowels as follows:

Consonants are pronounced largely as in English, with the following clarifications:

Not all consonants and vowels are pronounced distinctively by all people. The following variant pronunciations are allowed:

The stress is based on the classical Latin rule:

A secondary accent may be placed when necessary as the speaker deems appropriate.

Parts of speech

Though Peano removed the inflections of Latin from nouns and adjectives, he did not entirely remove grammatical gender, permitting the option of a feminine ending for occupations. The gender of animals is immutable. All forms of nouns end with a vowel and are taken from the ablative case, but as this was not listed in most Latin dictionaries, he gave the rule for its derivation from the genitive case. The plural is not required when not necessary, such as when a number has been specified, the plural can be read from the context, and so on; however, Peano gives the option of using the suffix -s to indicate it when needed. Verbs have few inflections of conjugation; tenses and moods are instead indicated by verb adjuncts. The result is a change to a positional language.


Particles that have no inflection in classical Latin are used in their natural form:


The form of nouns depends on the Latin declensions.

Latin declension number (genitive ending) 1: -ae 2: -i 3: -is 4: -us 5: -ei
Latino ending -a -o -e -u -e
Latin declension/nominative form Latin genitive Latino (Latin ablative) English
1st: rosa rosae rosa rose
2nd: laurus lauri lauro laurel
3rd: pax pacis pace peace
4th: casus casus casu case
5th: series seriei serie series

Those proper nouns written with the Roman alphabet are kept as close to the original as possible. The following are examples: München, New York, Roma, Giovanni.


Number Singular Plural
1st person me nos
2nd person te vos
3rd person illo (male), illa (female), id (neutral) illos
Reflexive se se


Verbs are formed from the Latin by dropping the final -re of the infinitive. Tense, mood, etc., are indicated by particles, auxiliary verbs, or adverbs, but none is required if the sense is clear from the context. If needed, the past may be indicated by preceding the verb with e, and the future with i.

There are specific endings to create the infinitive and participles:

Collateral endings

The endings -ra and -re are stressed in future and conditional verb forms, respectively.

Compound tenses

Composite tenses can be expressed with auxiliary words:

Adjectives and adverbs

Adjectives are formed as follows:

Adjectives can be used as adverbs if the context is clear, or cum mente or in modo can be used:

Comparative and superlative



As with Latin, neither the definite nor the indefinite article exists in Latino sine flexione. When necessary they may be translated with pronouns or words such as illo (it, that), isto or hoc (this), or uno (one):


Language examples

Latino es lingua internationale in occidente de Europa ab tempore de imperio romano, per toto medio aevo, et in scientia usque ultimo seculo. Seculo vigesimo es primo que non habe lingua commune. Hodie quasi omne auctore scribe in proprio lingua nationale, id es in plure lingua neo-latino, in plure germanico, in plure slavo, in nipponico et alio. Tale multitudine de linguas in labores de interesse commune ad toto humanitate constitute magno obstaculo ad progressu.

— Latin was the international language in the west of Europe from the time of the Roman Empire, throughout the Middle Ages, and in the sciences until the last century. The 20th century is the first that does not have a common language. Today almost all authors write in their own national languages, that is in Neo-Latin languages, in Germanic, in Slavic, in Japanese, and others. This multitude of languages in works of communal interest to the whole of humanity constitutes a large obstacle to progress.
The Lord's Prayer
Latino sine flexione version: Interlingua de IALA version Latin version: English (ELLC - 1988[19])

Nostro patre, qui es in caelos,
que tuo nomine fi sanctificato;
que tuo regno adveni;
que tuo voluntate es facto
sicut in caelo et in terra.
Da hodie ad nos nostro pane quotidiano,
et remitte ad nos nostro debitos,
sicut et nos remitte ad nostro debitores.
Et non induce nos in tentatione,
sed libera nos ab malo.

Patre nostre, qui es in le celos,
que tu nomine sia sanctificate;
que tu regno veni;
que tu voluntate sia facite
como in le celo, etiam super le terra.
Da nos hodie nostre pan quotidian,
e pardona a nos nostre debitas
como etiam nos los pardona a nostre debitores.
E non induce nos in tentation,
sed libera nos del mal.

Pater noster, qui es in caelis,
sanctificetur nomen tuum.
Adveniat regnum tuum.
Fiat voluntas tua,
sicut in caelo, et in terra.
Panem nostrum quotidianum da nobis hodie,
et dimitte nobis debita nostra,
sicut et nos dimittimus debitoribus nostris.
Et ne nos inducas in tentationem,
sed libera nos a malo.

Our Father (who are) in heaven,
hallowed be your name,
your kingdom come,
your will be done,
on earth as in heaven.
Give us today our daily bread.
Forgive us our sins
as we forgive those who sin against us.
Save us from the time of trial
and deliver us from evil.

Latin proverbs converted to Latino sine flexione
Latin Latino sine flexione English
Vox populi, vox Dei. Voce de populo, voce de Deo. The voice of the people is the voice of God.
Hodie mihi, cras tibi. Hodie ad me, cras ad te. It is my lot today, yours to-morrow.
Gratia gratiam generat, lis litem. Gratia genera gratia, lite genera lite. Goodwill begets goodwill, bickering begets bickering.
In medio stat virtus. Virtute sta in medio. Virtue stands in the middle.
Qui non laborat, non manducet. Qui non labora, non debe manducare. He who does not work, neither shall he eat.
Medice, cura te ipsum. Medico, cura te ipso. Physician, heal thyself.
De gustibus non est disputandum. Nos non debe disputare de gustu. There is no disputing about tastes.
Ars imitatio naturae est. Arte imita natura. Art imitates nature.
Do ut des. Me da ut te da. I give so that you give.
Designatio unius est exclusio alterius. Qui designa uno, exclude alio. Who chooses one excludes another.
Publius Cornelius Tacitus, De origine et situ Germanorum (Germania) (fragmentum initiale)
Latina classica (ex Vicifonte) Latino sine flexione / Interlingua (IL) de A.p.I. English (translated by A.J. Church and W.J. Brodribb, 1876)
Germania omnis a Gallis Raetisque et Pannoniis Rheno et Danuvio fluminibus, a Sarmatis Dacisque mutuo metu aut montibus separatur: cetera Oceanus ambit, latos sinus et insularum inmensa spatia complectens, nuper cognitis quibusdam gentibus ac regibus, quos bellum aperuit. Rhenus, Raeticarum Alpium inaccesso ac praecipiti vertice ortus, modico flexu in occidentem versus septentrionali Oceano miscetur. Danuvius molli et clementer edito montis Abnobae iugo effusus pluris populos adit, donec in Ponticum mare sex meatibus erumpat: septimum os paludibus hauritur. Fluvios Rheno et Danuvio separa toto Germania ab Gallos, Raetos et Pannonios; montes, aut metu mutuo, separa illo ab Sarmatas et Dacos: Oceano ambi ceteros, complectente sinus lato de mari et spatios immenso de insulas, ad certo gentes et reges recente cognito, aperto ab bello. Rheno, orto in vertice inaccesso et praecipite de Alpes Raetico, flecte se parvo versus occidente et misce se in Oceano septentrionale. Danuvio, effuso in jugo molle et clemente edito de monte Abnoba, visita plure populo, usque illo erumpe in mari Pontico per sex cursu: ore septimo perde se in paludes. Germany as a whole is separated from the Galli, the Rhaeti, and Pannonii, by the rivers Rhine and Danube; mountain ranges, or the fear which each feels for the other, divide it from the Sarmatae and Daci. Elsewhere ocean girds it, embracing broad peninsulas and islands of unexplored extent, where certain tribes and kings are newly known to us, revealed by war. The Rhine springs from a precipitous and inaccessible height of the Rhaetian Alps, bends slightly westward, and mingles with the Northern Ocean. The Danube pours down from the gradual and gently rising slope of Mount Abnoba, and visits many nations, to force its way at last through six channels into the Pontus; a seventh mouth is lost in marshes.


This article's "criticism" or "controversy" section may compromise the article's neutrality. Please help rewrite or integrate negative information to other sections through discussion on the talk page. (October 2021)

Peano formally defended the maxim that the best grammar is no grammar, bearing in mind the example of Chinese. (In modern linguistics, counter to popular and Peano's usage, grammar does not refer to morphological structures alone, but also to syntax and phonology, for example, which both Latino sine flexione and Chinese still have. In this sense, "languages without grammar" cannot exist.[20]) According to Lancelot Hogben, Peano's Interlingua still shares a major flaw with many other auxiliary languages, having "either too much grammar of the wrong sort, or not enough of the right".[9] (p. 10) Hogben argues that at least nouns and verbs should be easily distinguished by characteristic endings so that one can easily get an initial understanding of the sentence. Thus, in Peano's Interlingua, the verbs might be given some specific, standardized verbal form, such as the infinitive, which is sufficient in the Latin indirect speech. Instead, the raw imperative is proposed in De Latino Sine Flexione:

Lingua latino habet discurso directo, ut: "Amicitia inter malos esse non potest", et discurso indirecto: "(Verum est ) amicitiam inter malos esse non posse". Si nos utimur semper de discurso indirecto, in verbo evanescit desinentia de persona, de modo, et saepe de tempore. Sumimus ergo nomen inflexibile (...), sub forma magis simplice, qui es imperativo.

— [Translation: ] The Latin language has a direct discourse, like: "Friendness among the bad ones is not possible", and indirect discourse: "(It is true that ) friendness among the bad ones is not possible". If we always make use of indirect discourse, the desinences of person, mode, and (frequently) time, get vanished off the verb. So we take the name unflexed (...), under the simplest form, which is the imperative., Peano (1903, § 4)

According to Hogben, another handicap is the lack of a pure article, which might clearly indicate the nouns. Nevertheless, Peano occasionally suggested that illo (that) and uno (one) might be used as articles.

Once more according to Hogben, the syntax of Peano's Interlingua remained conservative:

[Peano's Interlingua] (...) has an aristocratic indifference to the necessity for simple rules of sentence-construction. The fact is that no pioneer of language-planning –least of all Peano– has undertaken the task of investigating what rules of word-order contribute most to intrinsic clarity of meaning and ease of recognition.

— Lancelot Hogben (1943, p. 11).

Reviewing the list of more widely known Latin titles, one might conclude that the sequence noun-adjective is the norm in Latin, yet the inverted sequence is also current.[21] The ratio is over 2 to 1 in a list of Latin titles commented by Stroh.[22] E.g. "Principia Mathematica". As for a sequence nominative-genitive, it may be the norm in Latin in a similar ratio. E.g. "Systema Naturae". Indeed, the sequence nominative-genitive must always be the norm in Peano's Interlingua, since the preposition de must introduce the genitive. Thus, Philosophiæ Naturalis Principia Mathematica would turn into Principio Mathematico de Philosophia Naturale. Since the function of both the adjective and the genitive is often the same, one might infer that the sequence noun-adjective might always be the norm.

Adiectivo qui deriva ab sustantivo vale genitivo: "aureo", "de auro".

— [Translation: ] An adjective derived from a substantive is equivalent to a genitive: "golden", "of gold"., Peano (1903, § 6).

See also


  1. ^ Grammatico section of the Vocabulario Commune, 1915
  2. ^ a b Peano, Giuseppe (1903). De Latino Sine Flexione. Lingua Auxiliare Internationale, Revista de Mathematica (Revue de Mathématiques), Tomo VIII, pp. 74-83. Fratres Bocca Editores: Torino.
  3. ^ "2017-022 | Iso 639-3".
  4. ^ Couturat, Louis (1901). La Logique de Leibniz. Paris.
  5. ^ Couturat, Louis (1903). Opuscules et fragments inédits de Leibniz. Paris.
  6. ^ Peano, Giuseppe (1904). Vocabulario de Latino internationale comparato cum Anglo, Franco, Germano, Hispano, Italo, Russo, Græco et Sanscrito [1]. Torino.
  7. ^ a b c Kennedy, Hubert (2006). Peano. Life and Works of Giuseppe Peano. Concord, CA: Peremptory Publications: p. 169 (a), p. 185 (b).
  8. ^ Academia pro Interlingua (Nov. 1909). Délégation pour l'Adoption d'une Langue Auxiliaire Internationale [2]. Discussiones (2): p. 37-9.
  9. ^ a b Hogben, Lancelot (1943). Interglossa. A draft of an auxiliary for a democratic world order, being an attempt to apply semantic principles to language design. [3] Harmondsworth, Middlesex, Eng. / New York: Penguin Books: p. 10-11. OCLC 1265553.
  10. ^ Silvia Roero, Clara (coord.) (2003). Le Riviste di Giuseppe Peano "Dipartimento di Matematica - Università di Torino". Archived from the original on 2011-07-22. Retrieved 2011-03-01. (CD-Rom N. 4). Dipartimento di Matematica dell' Università di Torino.
  11. ^ Peano, Giuseppe (1909). Vocabulario Commune ad linguas de Europa [4]. Cavoretto - Torino.
  12. ^ a b Peano, Giuseppe (1915). Vocabulario Commune ad Latino-Italiano-Français-English-Deutsch pro usu de interlinguistas [5]. Cavoretto - Torino.
  13. ^ Manuale Practico de Interlingua [6]. Pronomines: p. 29.
  14. ^ Manuale Practico de Interlingua [7]. De verbo: p. 10-25.
  15. ^ Manuale Practico de Interlingua [8]. De verbo: p. 10-25.
  16. ^ Manuale Practico de Interlingua [9]. Comparatione: p. 28.
  17. ^ Manuale Practico de Interlingua [10]. Comparatione: p. 29.
  18. ^ Manuale Practico de Interlingua [11]. Numeratione: p. 30-31.
  19. ^ Praying Together Archived 2013-10-29 at the Wayback Machine
  20. ^ Anderson, Catherine (15 March 2018), "1.4 Fundamental Properties of Language", Essentials of Linguistics, McMaster University, retrieved 2021-11-19
  21. ^ "Note on Peano's Interlingua" [12]. Updated: June 2014.
  22. ^ Stroh, Wilfried (2009). Le latin est mort. Vive la latin! [2007. Latein ist tot, es lebe Latein]. Paris: Les Belles Lettres. ISBN 978-2-251-34601-4.