The Tamil script evolved from an ancient southern form of the Brahmi script, but was also influenced by the Grantha script. It is currently used to write the Tamil language in the Indian state of Tamil Nadu as well as in Sri Lanka. Interestingly, the Tamil language is one of the oldest recorded languages in southern India. The earliest texts, written in the southern variant of Brahmi, date from just before the 1st century CE. Overtime the script changed, and by the 8th century CE the Tamil script has evolved into more or less its modern form.
The following is the basic Tamil script.
Unlike other South Asian scripts, Tamil does not have signs for voiceless aspirated (such as /kh/), voiced (/g/), and voiced aspirated stops (/gh/), which explains the relatively small number of signs in the Tamil script compared to other South Asian scripts. To write some of these sounds, some signs have multiple sound values: stands for both /ka/ and /ga/, for both /ca/ and /sa/, for /ta/, /da/, and /ða/, for /pa/ and /ba/, and so on. Sometimes these phonetic alterations are conditioned by the sound's position in the word (such as is /pa/ at the beginning of word or after a voiceless consonant, and /ba/ between vowels or after /m/), while other times they are somewhat random (such as can be both /ca/ and /sa/ at the beginning of a word). This confusion is due to phonological changes not reflected in the script, and to loanwords from Sanskrit and nearby languages.
Borrowings from Sanskrit also added some special letters to Tamil. The last row of six letters are called Grantha letters and have been used to write Sanskrit loanwords. Nowadays they are used to write words with English origin as well.
Similar to other South Asian scripts, a Tamil letter carries the inherent vowel of /a/. To change this vowel to another, extra strokes or signs are placed around the letter, as indicated by the following chart. Even the absence of the vowel is indicated by a dot written, called virama, above the letter.
While the diacritics for nearly all the vowels are relatively identical, the diacritics for /u/ and /u:/ vary between letters, as illustrated in the following example:
Another interesting feature of the Tamil script is how consonant clusters are written. In other South Asian scripts, letters are joined together to form a single sign, which often does not resemble the original letters. Tamil, on the other hand, each consonant in the cluster (except the last one) is represented by the corresponding letter plus the virama on top.