Vocab Speed for YouTube

Slow YouTube playback when captions contain unfamiliar English words.

Vocab Speed for YouTube turns captioned English videos into adaptive listening practice. Set your normal speed, slow speed, and unfamiliar-word threshold. While a YouTube video plays, Vocab Speed reads the visible caption, compares it with your known vocabulary list, and switches playback speed automatically. Easy sentences keep their natural pace. Harder sentences slow down so you can actually hear them. What it does: - Detects unfamiliar words in the current YouTube caption - Automatically switches between normal speed and slow speed - Shows a clean Vocab Board inside YouTube - Displays short Chinese meanings for unfamiliar words - Lets you replay the current or previous caption - Lets you blur subtitles for listening-first practice - Saves useful sentences into a local Phrase Queue - Connects to your own Supabase vocabulary table, or works with local words Vocab Speed is built for learners who shadow, listen repeatedly, and want video speed to respond to vocabulary difficulty rather than stay fixed for the whole video. Notes: - YouTube captions must be turned on. - The extension stores settings and phrase queue locally in Chrome. - Supabase keys are optional and user-provided. Do not use a service role key in the browser. - If automatic Chinese meaning lookup is enabled, only individual English words are sent to the translation endpoint.