India, March 25 -- Four years ago, with the lucidly written Wanderers, Kings, Merchants, Peggy Mohan traced the history of India through the languages its people speak. In her new book, Father Tongue, Motherland, the linguist goes further, exploring how languages in South Asia emerged through the mixing of old local grammars and the vocabularies of new arrivals. Drawing on the creole model of language evolution, she shows how these interactions shaped the region's modern tongues. Mohan grew up in Trinidad in a multilingual household-her father was of Indian origin, her mother Canadian-and heard English, Bhojpuri, and Creole spoken around her. She holds a PhD in linguistics from the University of Michigan and has taught at Harvard and Asho...