After Tamil Brahmi fell out of use, Tamil was written using a script called the vaṭṭeḻuttu amongst others such as Grantha and Pallava script. The current Tamil script consists of 12 vowels, 18 consonants and one special character, the āytam. The vowels and consonants combine to form 216 compound characters, giving a total of 247 characters (12 + 18 + 1 + 12 x 18). All consonants have an inherent vowel a, as with other Indic scripts. This inherency is removed by adding an overdot called a puḷḷi, to the consonantal sign. For example, ன is ṉa (with the inherent a) and ன் is ṉ (without a vowel). Many Indic scripts have a similar sign, generically called virama, but the Tamil script is somewhat different in that it nearly always uses a visible puḷḷi to indicate a dead consonant (a consonant without a vowel). In other Indic scripts, it is generally preferred to use a ligature or a half form to write a syllable or a cluster containing a dead consonant, although writing it with a visible virama is also possible. The Tamil script does not differentiate voiced and unvoiced plosives. Instead, plosives are articulated with voice depending on their position in a word, in accordance with the rules of Tamil phonology.
In addition to the standard characters, six characters taken from the Grantha script, which was used in the Tamil region to write Sanskrit, are sometimes used to represent sounds not native to Tamil, that is, words adopted from Sanskrit, Prakrit and other languages. The traditional system prescribed by classical grammars for writing loan-words, which involves respelling them in accordance with Tamil phonology, remains, but is not always consistently applied.