Learn languages from the YouTube you already watch
Dual subtitles under the player, every word clickable for a dictionary, and one click saves it as a flashcard with the sentence and the exact moment it was said. FSRS spaced repetition included free, not a paid add-on. Spanish, Japanese, French, German.
A source that found nothing is a measurement. A source that has not run is a gap. Neither means the launch lacks the thing.