References in Tolkapiyam
According to the historic Tamil chronicle Tolkappiyam, the limits of Tamilakam was between the hills of Venkatam in the north, and Cape Comorin in the south. Malayalam had not formed into a separate dialect at this period, and only one language, Tamil, was spoken from the Eastern to the Western Sea. According to A. Rajayyan, it is possible that the Tolkappiar and Sikiandiyar were "not aware of the Tamil part of the island of Lanka."
Read more about this topic: Tamilagam