The Persian language has between six and eight vowel phonemes and twenty-six consonant phonemes. It features contrastive stress and syllable-final consonant clusters.

The chart to the right reflects the vowels of many educated Persian speakers from Tehran.^[1][2]

The three vowels /æ/, /e/ and /o/ are traditionally referred to as 'short' vowels and the other three (/ɒː/, /iː/ and /uː/) as 'long' vowels. In fact the three 'short' vowels are short only when in an open syllable (i.e. a syllable ending in a vowel) that is non-final (but can be unstressed or stressed), e.g. صدا [seˈdɒː] 'sound', خدا [xoˈdɒː] 'God'. In a closed syllable (i.e. a syllable ending in a consonant) that is unstressed, they are around sixty percent as long as a long vowel; this is true for the 'long' vowel /iː/ as well. Otherwise the 'short' and 'long' vowels are all pronounced long. Example: سفتر [seˑfˈtʰæːɾ] 'firmer'.^[3]

When the short vowels are in open syllables, they are also unstable and tend in informal styles to assimilate in quality to the following long vowel, sometimes in formal situations also. Thus دویست [deˈviːst] 'two hundred' becomes [diˈviːst], شلوغ [ʃoˈluːɢ] 'crowded' becomes [ʃuˈluːɢ], رسیدن [ræsiːˈdæːn] 'to arrive' becomes [resiːˈdæːn] and so on.^[3]

Word-final /o/ is rare except for تو /to/ ('you' [singular]) and nouns of foreign origin, and word-final /æ/ is very rare in Iranian Persian, an exception being نه /næ/ ('no'). The word-final /æ/ in Early New Persian mostly shifted to /e/ in contemporary Iranian Persian (often romanized as ⟨eh⟩, meaning [e] is also an allophone of /æ/ in word-final position in contemporary Iranian Persian), but is preserved in the Eastern dialects. The short vowel [e] is the most common short vowel that is pronounced in final open syllables.

The status of diphthongs in Persian is disputed.^[4][5] Some authors list /ei̯, ou̯, ɒi̯, oi̯, ui̯/,^[4] others list only /ei̯/ and /ou̯/, but some do not recognize diphthongs in Persian at all.^[4][5] A major factor that complicates the matter is the change of two classical and pre-classical Persian diphthongs: /ai̯/ > /ei̯/ and /au̯/ > /ou̯/. This shift occurred in Iran but not in some modern varieties (particularly of Afghanistan).^[4] Morphological analysis also supports the view that the alleged Persian diphthongs are combinations of the vowels with /j/ and /w/.^[5]

The Persian orthography does not distinguish between the diphthongs and the consonants /j/ and /w/; that is, they both are written with ی and و respectively.

/ou̯/ becomes [oː] in the colloquial Tehran dialect but is preserved in other Western dialects and standard Iranian Persian.^{[citation needed]}

For Western Persian:

The variety of Afghanistan has also preserved these two Classic Persian vowels:

In the modern Persian alphabet, the short vowels /e/, /o/, /æ/ are usually left unwritten, as is normally done in the Arabic alphabet. (See Arabic phonology § Vowels.)

Early New Persian inherited from Middle Persian eight vowels: three short i, a, u and five long ī, ē, ā, ō, ū (in IPA: /i a u/ and /iː eː aː oː uː/). It is likely that this system passed into the common Persian era from a purely quantitative system into one where the short vowels differed from their long counterparts also in quality: i > [ɪ]; u > [ʊ]; ā > [ɑː]. These quality contrasts have in modern Persian varieties become the main distinction between the two sets of vowels.^[6]

The inherited eight-vowel inventory is retained without major upheaval in Dari, which also preserves quantitative distinctions.^[7]

In Western Persian, two of the vowel contrasts have been lost: those between the tense mid and close vowels. Thus ē, ī have merged as [iː], while ō, ū have merged as [uː]. In addition, the lax close vowels have been lowered: i > [e], u > [o]; this vowel change also happened in Dari. The lax open vowel has become fronted: a > [æ], and in word-final position further raised to [e]. Modern Iranian Persian does not feature distinctive vowel length.^[8]

In both varieties ā is more or less labialized, as well as raised in Dari. Dari ō is also somewhat fronted.^[7]

Tajiki has also lost two of the vowel contrasts, but differently from Western Persian: here the tense/lax contrast among the close vowels has been eliminated. That is, i, ī have merged as /ɪ/, and u, ū have merged as /ʊ/. The other tense back vowels have shifted as well. Mid ō has shifted front: /ɵ/ or /ʉ/, a vowel usually romanized as ů. Open ā has been labialized and raised to an open-mid vowel /ɔ/.

Loanwords from Arabic generally undergo these changes as well.

The following chart summarizes the later shifts into modern Tajik, Dari, and Western Persian.^[7][9]

Early New Persian	Dari	Tajiki	Western Persian	Example	Tajik	Romanization	English
/a/	/a/	/a/	/æ/	شب	шаб	šab	night
/aː/	/ɒ̝ː/	/ɔ/	/ɒː/	باد	бод	bâd	wind
/i/	/e/	/ɪ/	/e/	دل	дил	dil	heart
/iː/	/iː/		/iː/	شیر	шир	šîr	milk
/eː/	/e̞ː/	/e̞/		شیر	шер	šer	lion
/aj/	/aj/	/aj/	/ej/	کی	кай	kay	when
/u/	/o/	/ʊ/	/o/	گل	гул	gul	flower
/uː/	/uː/		/uː/	نور	нур	nûr	light
/oː/	/ö̞ː/	/ɵ/		روز	рӯз	roz	day
/aw/	/aw/	/av/	/ow/	نو	нав	naw	new

Notes:

• In Central Iranian Persian /ɣ/ and /q/ have merged into [ɣ~ɢ]; as a voiced velar fricative [ɣ] when positioned intervocalically and unstressed, and as a voiced uvular stop [ɢ] otherwise. Many dialects within Iran have well preserved the distinction. ^[10][11][12]

Alveolar stops /t/ and /d/ are either apical alveolar or laminal denti-alveolar. The voiceless obstruents /p, t, t͡ʃ, k/ are aspirated much like their English counterparts: they become aspirated when they begin a syllable, though aspiration is not contrastive.^[13] The Persian language does not have syllable-initial consonant clusters (see below), so unlike in English, /p, t, k/ are aspirated even following /s/, as in هستم /ˈhæstæm/ ('I exist').^[14] They are also aspirated at the end of syllables, although not as strongly.

The velar stops /k, ɡ/ are palatalized before front vowels or at the end of a syllable.

In Classical Persian, the uvular consonants غ and ق denoted the original Arabic phonemes, the fricative [ʁ] and the plosive [q], respectively. In modern Tehrani Persian (which is used in the Iranian mass media, both colloquial and standard), there is no difference in the pronunciation of غ and ق. The actual realisation is usually that of a voiced stop [ɢ], but a voiced fricative [ɣ]~[ʁ] is common intervocalically. The classic pronunciations of غ and ق are preserved in the eastern varieties, Dari and Tajiki, as well as in the southern varieties (e.g. Zoroastrian Dari language and other Central / Central Plateau or Kermanic languages).

Some Iranian speakers show a similar merger of ج and ژ, such that [d͡ʒ] alternates with [ʒ], with the latter being restricted to intervocalic position.

Some speakers front /h/ to a voiceless palatal fricative [ç] in the vicinity of /i/, especially in syllable-final position. The velar/uvular fricatives are never fronted in such a way.

The alveolar flap /ɾ/ has a trilled allophonic variant [r] at the beginning of a word (it is sometimes a free variation between a trill [r] and a flap [ɾ]);^[13] the trill [r] as a separate phoneme occurs word-medially especially in loanwords of Arabic origin as a result of gemination of [ɾ]. An approximant [ɹ] also occurs as an allophone of /ɾ/ before /t, d, s, z, ʃ, l, ʒ/; [ɹ] is sometimes in free variation with [ɾ] in these and other positions, such that فارسی ('Persian') is pronounced [fɒːɹˈsiː] or [fɒːɾˈsiː] and سقرلات ('scarlet') [sæɣeɹˈlɒːt] or [sæɣeɾˈlɒːt]. /r/ is sometimes realized as a long approximant [ɹː].

The velar nasal [ŋ] is an allophone of /n/ before /k, ɡ/, and the uvular nasal [ɴ] before /q/.

/f, k, s, ʃ, x/ may be voiced to, respectively, [v, ɡ, z, ʒ, ɣ] before voiced consonants; /n/ may be bilabial [m] before bilabial consonants. Also /b/ may in some cases change into [β], or even [v]; for example باز ('open') may be pronounced [bɒːz] as well as [βɒːz] or [vɒːz] and/or [vɒː], colloquially.

The pronunciation of و [w] in Classical Persian shifted to [v] in Iranian Persian and Tajik, but is retained in Dari. In modern Persian [w] may be lost if preceded by a consonant and followed by a vowel in one whole syllable, e.g. خواب /xwɒb/ ~ [xɒb] 'sleep', as Persian has no syllable-initial consonant clusters (see below).

In standard Iranian Persian, the consonants /ʁ/ and /ɢ/ are pronounced identically.

Consonants, including /ʔ/ and /h/, can be geminated, often in words from Arabic. This is represented in the IPA either by doubling the consonant, سیّد саййид [sejˈjed], or with the length marker ⟨ː⟩, [seˈjːed].^[15][16]

Syllables may be structured as (C)(S)V(S)(C(C)).^[13][17]

Persian syllable structure consists of an optional syllable onset, consisting of one consonant; an obligatory syllable nucleus, consisting of a vowel optionally preceded by and/or followed by a semivowel; and an optional syllable coda, consisting of one or two consonants. The following restrictions apply:

• Onset
  • Consonant (C): Can be any consonant. (Onset is composed only of one consonant; consonant clusters are only found in loanwords, sometimes an epenthetic /æ/ is inserted between consonants.)
• Nucleus
  • Semivowel (S)
  • Vowel (V)
  • Semivowel (S)
• Coda
  • First consonant (C): Can be any consonant.
  • Second consonant (C): Can also be any consonant (mostly /d/, /k/, /s/, /t/, & /z/).

The Persian word-accent has been described as a stress accent by some,^[18] and as a pitch accent by others.^[19] In fact the accented syllables in Persian are generally pronounced with a raised pitch as well as stress; but in certain contexts words may become deaccented and lose their high pitch.^[20][21]

From an intonational point of view, Persian words (or accentual phrases) usually have the intonation (L +) H* (where L is low and H* is a high-toned stressed syllable), e.g. کتاب /keˈtɒ́b/ 'book'; unless there is a suffix, in which case the intonation is (L +) H* + L, e.g. کتابم /keˈtɒ́b-æm/ 'my book'. The last accent of a sentence is usually accompanied by a low boundary tone, which produces a falling pitch on the last accented syllable, e.g. کتاب بود /keˈtɒ̂b buːd/ 'it was a book'.^[20][21]

When two words are joined in an اضافه ezafe construction, they can either be pronounced accentually as two separate words, e.g. مردم اینجا /mærˈdóm-e inˈd͡ʒɒ́/ 'the people (of) here', or else the first word loses its high tone and the two words are pronounced as a single accentual phrase: /mærˈdom-e inˈd͡ʒɒ́/. Words also become deaccented following a focused word; for example, in the sentence نامه‌ی مامانم بود رو میز /nɒˈme-ye mɒˈmɒn-æm bud ru miz/ 'it was my mom's letter on the table' all the syllables following the word مامان /mɒˈmɒn/ 'mom' are pronounced with a low pitch.^[20]

Knowing the rules for the correct placement of the accent is essential for proper pronunciation.^[22]

1. Accent is heard on the last stem-syllable of most words.
2. Accent is heard on the first syllable of interjections, conjunctions and vocatives. E.g. بله /ˈbæle/ ('yes'), نخیر /ˈnæxeir/ ('no, indeed'), ولی /ˈvæli/ ('but'), چرا /ˈtʃeɾɒ/ ('why'), اگر /ˈæɡæɾ/ ('if'), مرسی /ˈmeɾsi/ ('thanks'), خانم /ˈxɒnom/ ('Ma'am'), آقا /ˈɒɢɒ/ ('Sir'); cf. 4-4 below.
3. Never accented are:
   1. personal suffixes on verbs (/-æm/ ('I do..'), /-i/ ('you do..'), .., /-ænd/ ('they do..') (with two exceptions, cf. 4-1 and 5 below);
   2. the possessive and pronoun-object suffixes, /-æm/, /-et/, /-eʃ/, &c.
   3. a small set of very common noun enclitics: the /ezɒfe/ اضافه (/-e/, /-je) ('of'), /-ɾɒ/ a definite direct object marker, /-i/ ('a'), /-o/ ('and');
4. Always accented are:
   1. the personal suffixes on the positive future auxiliary verb (exception to 3-1 above);
   2. the negative verb prefix /næ-/, /ne-/, if present;
   3. if /næ-/, /ne-/ is not present, then the first non-negative verb prefix (e.g. /mi-/ ('-ing'), /be-/ ('do!') or the prefix noun in compound verbs (e.g. کار /kɒr/ in کار می‌کردم /ˈkɒr mi-kærdæm/);
   4. the last syllable of all other words, including the infinitive ending /-æn/ and the participial ending /-te/, /-de/ in verbal derivatives, noun suffixes like /-i/ ('-ish') and /-eɡi/, all plural suffixes (/-hɒ/, /-ɒn/), adjective comparative suffixes (/-tæɾ/, /-tæɾin/), and ordinal-number suffixes (/-om/). Nouns not in the vocative are stressed on the final syllable: خانم /xɒˈnom/ ('lady'), آقا /ɒˈɢɒ/ ('gentleman'); cf. 2 above.
5. In the informal language, the present perfect tense is pronounced like the simple past tense. Only the word-accent distinguishes between these tenses: the accented personal suffix indicates the present perfect and the unstressed one the simple past tense (exception to 3-1 above):

When spoken formally, Iranian Persian is pronounced as written. But colloquial pronunciation as used by all classes makes a number of very common substitutions. Note that Iranians can interchange colloquial and formal sociolects in conversational speech. They include:^[22][23]

• In the Tehran accent and also most of the accents in Central and Southern Iran, the sequence /ɒn/ in the colloquial language is nearly always pronounced [un]. The only common exceptions are high prestige words, such as قرآن [ɢoɾˈʔɒn] ('Qur'an'), and ایران [ʔiˈɾɒn] ('Iran'), and foreign nouns (both common and proper), like the Spanish surname بلتران Beltran [belˈtɾɒn], which are pronounced as written. A few words written as /ɒm/ are pronounced [um], especially forms of the verb آمدن /ɒmæˈdæn/ ('to come').
• In the Tehran accent, the unstressed direct object suffix marker را /ɾɒ/ is pronounced /ɾo/ after a vowel, and /o/ after a consonant.
• The 2nd and 3rd person plural verb subject suffixes, written /-id/ and /-ænd/ respectively, are pronounced [-in] and [-æn].
• The stems of many frequently-occurring verbs have a short colloquial form, especially است /æst/ ('he/she is'), which is colloquially shortened to /e/ after a consonant or /s/ after a vowel. Also, the stems of verbs which end in /h/, /v/ or a vowel are shortened; e.g. می‌خواهم /ˈmixɒːhæm/ ('I want') → [ˈmixɒːm], and می‌روم /ˈmiɾævæm/ ('I go' → [ˈmiɾæm].

• Persian to Persian dictionary with IPA pronunciation

Wikimedia Commons has media related to Persian pronunciation.

• Virtual Persian Keyboard