Seeing as how India and China are close geographically and both boast vast ancient history why is it that their language hasn't had any direct influence on each other? Or has it and I'm not aware of it?
EDIT: Sino-Tibetan** languages
Sino-Tibetan languages are widespread in parts of India, particularly Northeast India and the Himalayas. They didn't spread further for the same reason Indo-Aryan languages didn't spread in China - both countries are isolated by high mountain ranges. Mongoloid Sino-Tibetan speakers couldn't colonize the fertile Indo-Gangetic plain, because it was already densely populated by Indian agriculturalists, so they stayed up in the mountains.