InterSub

InterSub transforms how learners acquire new languages by overlaying interactive dual subtitles on videos across major streaming platforms including YouTube, Netflix, Prime Video, and Coursera. The tool displays content in both your native language and target language simultaneously, enabling natural acquisition through real-world media consumption rather than isolated vocabulary drills. The platform intelligently handles scenarios where native-language subtitles aren't available by providing real-time AI translations. Users can hover over any word to instantly access contextual definitions and translations powered by artificial intelligence, turning passive viewing into active learning moments. This interactive approach helps learners understand not just individual words, but how they function within authentic conversational contexts. InterSub automatically saves every word you translate to a Personal Wordbook, creating a customized study resource built from content you actually watch. This wordbook syncs across mobile applications and Telegram bots, allowing you to review vocabulary during commutes or downtime. The tool also supports word lookups across virtually any website and includes collocation detection, helping learners grasp the subtle language patterns that distinguish fluent speakers from intermediate students. With remote control functionality and broad platform compatibility, InterSub adapts to your viewing habits rather than forcing you into rigid study schedules. Whether you're watching entertainment, educational courses, or professional content, the tool works seamlessly in the background, building your language skills through consistent exposure to native-level material.