To qualify as a classical tradition, a language must fit several criteria: it should be ancient, it should be an independent tradition that arose mostly on its own not as an offshoot of another tradition, and it must have a large and extremely rich body of ancient literature.  Unlike the other modern languages of India, Tamil meets each of these requirements.  It is extremely old (as old as Latin and older than Arabic); it arose as an entirely independent tradition, with almost no influence from Sanskrit or other languages; and its ancient literature is indescribably vast and rich.

It seems strange to me that I should have to write an essay such as this claiming that Tamil is a classical literature — it is akin to claiming that India is a great country or Hinduism is one of the world’s great religions.  The status of Tamil as one of the great classical languages of the world is something that is patently obvious to anyone who knows the subject.  To deny that Tamil is a classical language is to deny a vital and central part of the greatness and richness of Indian culture.

ஜியார்ஜ் ஹார்ட் — http://tamil.berkeley.edu/tamil-chair/letter-on-tamil-as-a-classical-language