The languages belonging to the South-Dravidian sub-group of the Dravidian languages exhibit various degrees of genetic relationship. Though the common retentions and the later innovations have led to an indisputable consensus on broad issues, details regarding the finer genetic relationship remain to be worked out. This paper tries to analyse the genetic relationship between Tamil and Malayalam in the light of some sound changes, and also discusses the problems involved in the interpretation of the linguistic material.
All the comparative evidence points to a closer relationship between Tamil and Malayalam. They preserve alike some of the Proto-South-Dravidian features such as *ḻ, *ṛṛ besides innovating sound changes such as *k– > c–. On the basis of a number of common phonological and morphological features, scholars concluded that at the stage known as late Old and early Middle Tamil, Tamil and Malayalam were most probably basically one language with pre- Malayalam as a diverging western dialect of the spoken form of that common language. The innovations which appeared in the ninth- and tenth-century West Coast inscriptions were linked with the similar tendencies observed in colloquial Tamil. The oldest Malayalam inscriptions and literary texts are not earlier than about the ninth century A.D. Since this period is contemporaneous with Middle Tamil, it was argued that the development of a separate language had to be dated to that period.