Sounds

Tamil phonology is characterised by the presence of retroflex consonants and multiple rhotics. Tamil does not distinguish phonologically between voiced and unvoiced consonants; phonetically, voice is assigned depending on a consonant's position in a word. Tamil phonology permits few consonant clusters, which can never be word initial. Native grammarians classify Tamil phonemes into vowels, consonants, and a "secondary character", the āytam.

Vowels

Tamil vowels are called uyireḻuttu (uyir – life, eḻuttu – letter). The vowels are classified into short (kuṟil) and long (neṭil) (with five of each type) and two diphthongs, /ai/ and /au/, and three "shortened" (kuṟṟiyl) vowels.

The long vowels are about twice as long as the short vowels. The diphthongs are usually pronounced about 1.5 times as long as the short vowels, though most grammatical texts place them with the long vowels.

	Short			Long
	Front	Central	Back	Front	Central	Back
Close	i		u	iː		uː
	இ		உ	ஈ		ஊ
Mid	e		o	eː		oː
	எ		ஒ	ஏ		ஓ
Open		a		(ai)	aː	(aw)
		அ		ஐ	ஆ	ஒள

Consonants

Tamil consonants are known as meyyeḻuttu (mey—body, eḻuttu—letters). The consonants are classified into three categories with six in each category: valliṉam—hard, melliṉam—soft or Nasal, and iṭayiṉam—medium.

Unlike most Indian languages, Tamil does not distinguish aspirated and unaspirated consonants. In addition, the voicing of plosives is governed by strict rules in centamiḻ. Plosives are unvoiced if they occur word-initially or doubled. Elsewhere they are voiced, with a few becoming fricatives intervocalically. Nasals and approximants are always voiced.

As commonplace in languages of India, Tamil is characterised by its use of more than one type of coronal consonants. Retroflex consonants include the retroflex approximant /ɻ/ (ழ) (example Tamil), which among the Dravidian languages is also found in Malayalam (example Kozhikode), disappeared from Kannada in pronunciation at around 1000 AD (the dedicated letter is still found in Unicode), and was never present inTelugu. Dental and alveolar consonants also contrast with each other, a typically Dravidian trait not found in the neighboring Indo-Aryan languages. In spoken Tamil, however, this contrast has been largely lost, and even in literary Tamil, ந and ன may be seen as allophonic.

A chart of the Tamil consonant phonemes in the International Phonetic Alphabet follows:

	Labial	Dental	Alveolar	Retroflex	Palatal	Velar
Plosives	p (b)	t̪ (d̪)		ʈ (ɖ)	tʃ (dʒ)	k (ɡ)
	ப	த		ட	ச	க
Nasals	m	n̪	n	ɳ	ɲ	ŋ
	ம	ந	ன, ந	ண	ஞ	ங
Tap		ɾ̪
		ர
Trill			r
			ற
Central approximants	ʋ			ɻ	j
	வ			ழ	ய
Lateral approximants		l̪		ɭ
		ல		ள

Phonemes in brackets are voiced equivalents. Both voiceless and voiced forms are represented by the same character in Tamil, and voicing is determined by context. The sounds /f/ and /ʂ/ are peripheral to the phonology of Tamil, being found only in loanwords and frequently replaced by native sounds. There are well-defined rules for elision in Tamil categorised into different classes based on the phoneme which undergoes elision.

Āytam

Classical Tamil also had a phoneme called the Āytam, written as ‘ஃ'. Tamil grammarians of the time classified it as a dependent phoneme (or restricted phoneme ) (cārpeḻuttu), but it is very rare in modern Tamil. The rules of pronunciation given in the Tolkāppiyam, a text on the grammar of Classical Tamil, suggest that the āytam could have glottalised the sounds it was combined with. It has also been suggested that theāytam was used to represent the voiced implosive (or closing part or the first half) of geminated voiced plosives inside a word. The Āytam, in modern Tamil, is also used to convert pa to fa (not the retroflex zha[ɻ]) when writing English words using the Tamil script.

Numerals and symbols

Apart from the usual numerals, Tamil also has numerals for 10, 100 and 1000. Symbols for day, month, year, debit, credit, as above, rupee, and numeral are present as well.

0	1	2	3	4	5	6	7	8	9	10	100	1000
௦	௧	௨	௩	௪	௫	௬	௭	௮	௯	௰	௱	௲

day	month	year	debit	credit	as above	rupee	numeral
௳	௴	௵	௶	௷	௸	௹	௺