The Tamil language echoes across the United States, Prime Minister Narendra Modi said at Chennai airport today, adding to a number of references to the nation's linguistic diversity that he made in the past week, which included quoting from an ancient Tamil poet at the United Nations General Assembly. PM Modi, in the Tamil Nadu capital to attend the annual convocation ceremony of the Indian Institute of Technology, also said he took it upon himself to "teach everyone that this (Tamil) is one of the ancient languages".