In 1996, a Cornell University graduate student from India took a VCR break from working on his dissertation to watch Pedro Almodóvar's "Women on the Verge of a Nervous Breakdown." Struggling with the comedy's rapid-fire Spanish, the student, Brij Kothari, wished for subtitles in the same language: If he could read along in Spanish, he felt sure his proficiency would improve. This prompted another thought: If viewers back home in India could watch Bollywood musicals with Hindi subtitles, would it help them learn to read their own language?

The...