In addition to its various dialects, Tamil exhibits different forms: a classical literary style modelled on the ancient language (sankattamiḻ), a modern literary and formal style (centamiḻ), and a modern colloquial form (koṭuntamiḻ). These styles shade into each other, forming a stylistic continuum. For example, it is possible to write centamiḻ with a vocabulary drawn from caṅkattamiḻ, or to use forms associated with one of the other variants while speaking koṭuntamiḻ.
In modern times, centamiḻ is generally used in formal writing and speech. For instance, it is the language of textbooks, of much of Tamil literature and of public speaking and debate. In recent times, however,koṭuntamiḻ has been making inroads into areas that have traditionally been considered the province of centamiḻ. Most contemporary cinema, theatre and popular entertainment on television and radio, for example, is in koṭuntamiḻ, and many politicians use it to bring themselves closer to their audience. The increasing use of koṭuntamiḻ in modern times has led to the emergence of unofficial ‘standard' spoken dialects. In India, the ‘standard' koṭuntamiḻ is based on ‘educated non-Brahmin speech', rather than on any one dialect, but has been significantly influenced by the dialects of Thanjavur and Madurai. In Sri Lanka the standard is based on the dialect of Jaffna.