Hemant Singh Yadav, a lean and sprightly 15-year-old, was sent by his parents to a summer camp to learn to speak Sanskrit, or what he calls the language of the gods.

He had studied the 4,000-year-old classical Indian language at school for six years. He knew its grammar and could chant the ancient hymns. But he could not converse in it. During a two-week course at the camp, Sanskrit Samvad Shala, he had no choice: He was forbidden to speak any other language.

"At first I thought it was impossible. The teachers and attendants spoke to us only in Sanskrit, and I did not understand anything," said Hemant, one of the 150 students gathered inside a Hindu temple on the outskirts of New Delhi. "I knew big, heavy bookish words before, but not the simple ones. But now Sanskrit feels like an everyday language."

Such camps, run by volunteers from Hindu nationalist groups, are designed to promote a language long dismissed as dead, and to instill in Hindus religious and cultural pride. Many Sanskrit speakers, though, believe that the camps are a steppingstone to a higher goal: turning back the clock and making Sanskrit modern India's spoken language.