Tamil phonology

[1] Tamil phonology permits few consonant clusters, which can never be word initial.

Tamil has two diphthongs: /aɪ̯/ ஐ and /aʊ̯/ ஔ, the latter of which is restricted to a few lexical items.

Word final /u/ is pronounced as [ɯ~ɨ], it is called a குற்றியலுகரம் (kuṟṟiyalukaram) "short u" (as it has only half a sound unit, compared to 1, 1.5 or 2 of other vowels) in tolkāppiyam and it is unrounded even in literary Tamil; in spoken Tamil it can occur medially as well in some words after the first syllable.

Word final [u] occurs in some names, chiefly nicknames like rājēndraṉ as rāju.

[5] In spoken Tamil sometimes an epenthetic vowel u is added to words ending in consonants, e.g. nil > nillu, āḷ > āḷu, nāḷ > nāḷu (nā in some dialects), vayal > vayalu etc.

[7] Additionally, the front long vowels /eː/ and /iː/ are subject to retraction when present in the first syllable of a bisyllabic word and followed by a retroflex consonant.

The presence and degree of retraction for each vowel may be different; it varies between dialects and even individual speakers.

[7] For some speakers in spoken Tamil the front vowels /i(:), e(:)/ get rounded to their corresponding rounded back vowels when they are after a labial consonant /m, p, ʋ/ and before a retroflex consonant, some words with it are quite acceptable like பெண் /peɳ/ > பொண்/பொண்ணு [poɳ~poɳ:ɯ] but others like வீடு /ʋi:ʈu/ > வூடு [ʋu:ɖɯ] are less accepted and may even be considered vulgar.

Among the other Dravidian languages, the retroflex approximant also occurs in Malayalam, Badaga, old Telugu and old Kannada.

The proto-Dravidian alveolar stop *ṯ developed into an alveolar trill /r/ in the Southern and South Central Dravidian languages while *ṯṯ and *ṉṯ remained (modern ṟṟ, ṉṟ).

[2] [n̪] occurs in other places from compounding of words starting with it and geminates from sandhi, eg.

In modern Tamil, however, voiced plosives occur initially in loanwords.

There are also cases where it became t mutalai/mutaḷai/mucali, Kannada mosaḷe and disappeared after lengthening the previous vowel nilā, Kodava nelaci.

The rules of pronunciation given in the Tolkāppiyam, a text on the grammar of old Tamil, says that the āytam in old Tamil patterned with semivowels and it occurred after a short vowel and before a stop; it either lengthened the previous vowel, geminated the stop or was lost if the following segment is phonetically voiced in the environment.

[26] It is said to be the descendant of Proto Dravidian laryngeal *H. The āytam in modern Tamil is used to transcribe foreign phones like ஃப் (ஃp) for [f], ஃஜ (ஃj) for [z], ஃஸ (ஃs) for [z, ʒ] and ஃக (ஃk) for [x], similar to a nuqta.

Unlike most Indic scripts, Tamil does not have distinct letters for aspirated consonants and they are found as allophones of the normal stops.

The Tamil script also lacks distinct letters for voiced and unvoiced stops as their pronunciations depend on their location in a word.

Some loan words are pronounced in Tamil as they were in the source language, even if this means that consonants which should be unvoiced according to the Tolkāppiyam are voiced.