YouTube Subtitle Sidekick

Learn English from the YouTube videos you already enjoy. YouTube Subtitle Sidekick turns YouTube into an interactive English-learning experience. Follow rolling subtitles beside the video, understand unfamiliar language in context, and build a vocabulary you’ll actually remember. Learn while you watch Subtitles automatically follow the video and highlight the current line. Click any word for a definition, pronunciation, and phonetic spelling—without leaving YouTube. Translate subtitle lines when you need help, then replay the exact moment to hear the language again. Built for deliberate practice - Interactive subtitles — Follow the current line as the video plays. - Instant word lookup — Click a word for definitions from Wiktionary and Free Dictionary, pronunciation, and spelling. - CEFR difficulty colors — See B1, B2, C1, and C2 vocabulary at a glance. - Inline translation — Translate subtitle lines into one of 12 languages, including Chinese. - Words to Learn — Get a ranked list of unfamiliar words from the current video, based on frequency and difficulty. - Vocabulary notebook — Save words and sentences with their original context, notes, and video timestamp. - Spaced-repetition review — Review with Again, Good, and Easy ratings, plus a multiple-choice quiz. - Vocabulary lists and export — Organize learning by topic, video, or level, then export your vocabulary. - Coverage meter — See how much of a video’s unique vocabulary you already know. - Replay and A/B loop — Jump back to a saved word’s sentence or repeat a line for shadowing practice. - Comprehension mode — Blur subtitles to challenge your listening before revealing the answer. Learn one word, one sentence, and one video at a time.