I probably have es-ar or es as the main language, so my videos are autotranslated with a horrible robotic voice until I choose English. Then when I see a video in Spanish, it get autotranslated with a horrible robotic voice to English and I have to switch back.

I have set Spanish(LA), Spanish and English as main languages, but somehow my browser sends "es-419,es;q=0.9" and I see no "en" in the list.

The list of languages may have a short list of languages at the top. Wikipedia uses the most recent languages so it's easy to switch.