YouTube Auto Native Subtitles от MonsterWhat

Tired of subtitles stuck in the previous video's language? YouTube remembers your last subtitle choice and reapplies it everywhere — so a Spanish video inherits English subtitles and vice versa. This extension fixes that: every video gets subtitles in its own language, automatically.

How it works:
• Detects each video's native language and switches the subtitle track to match, using your own per-language rules (Spanish→Spanish, English→English out of the box).
• Falls back to the language of your choice when no rule matches — translating an existing track when the wanted language has none of its own.
• Handles dubbed videos too: configurable audio-track rules switch multi-audio videos to your language so the right captions become available.
• Never turns captions on or off — it only changes the track language. Your CC button stays yours.

Everything is configurable from the toolbar-button settings page (rules, fallbacks, audio), applied live to open tabs, and stored only on your device. No accounts, no tracking, no network requests — the extension only talks to YouTube's player on youtube.com video pages.