He earned two master's degrees from Delhi University, in Hindi and English.
He received his Ph.D. from the University of Pennsylvania in 1973 for his dissertation entitled "Pronominal Usage in Hindi: A Sociolinguistic Study", advised by Dell Hathway Hymes and Franklin Southworth.
[3] After teaching Hindi at Penn, in 1973 he returned to India and joined the Linguistics department at Jawaharlal Nehru University.
In 1982, he formed Ratna Sagar, a publishing house for textbooks and teaching materials.
Jain continued working in linguistics alongside running Ratna Sagar, notably coauthoring The Indo-Aryan Languages with George Cardona, a comprehensive and foundational volume covering the Indo-Aryan language family.