I'm French but have everything in English (system, browser & YouTube). I've seen a lot of French YouTube videos with their title auto-translated in English a couple of weeks after their diffusion.
(Bad for two reasons: (1) badly translated titles, sometimes hilariously so, and (2) the algorithm recommends me videos I have already watched. I guess (2) is because I don't usually watch the last 20 seconds, the static "my last video was", whatever it's called, so YouTube must think I haven't watched the video. Most times, the red gauge below the video thumbnail shows half-full even though I've watched the video minus these 20 seconds. There's still room for improvements...)
(Bad for two reasons: (1) badly translated titles, sometimes hilariously so, and (2) the algorithm recommends me videos I have already watched. I guess (2) is because I don't usually watch the last 20 seconds, the static "my last video was", whatever it's called, so YouTube must think I haven't watched the video. Most times, the red gauge below the video thumbnail shows half-full even though I've watched the video minus these 20 seconds. There's still room for improvements...)