InterSub

InterSub, built by InterSub Inc. based in New York, is a browser extension that enables language learning by providing dual subtitles and instant translations while watching videos on streaming platforms. Dual subtitles display target-language and native-language subtitles side-by-side, instant translations give AI-generated definitions and context-based translations when hovering over unfamiliar words, and a personal wordbook automatically saves looked-up words to a vocabulary list for review. Multi-platform support covers YouTube, Netflix, Prime Video, HBO, Crunchyroll, TED, Coursera, Udemy, and LinkedIn Learning, collocation detection recognizes English phrasal verbs, idioms, and compound nouns, and remote control lets a smartphone look up words while watching on a larger screen.