So, I had to make the same settings change, otherwise google would keep putting French searches before English ones (despite the fact that I searched with English keywords).
I don't remember how I found this, but it might something along the lines of "I'm really annoyed today, let's fix this NOW". When you speak 2 languages or more, and they don't match with your location, Google, Microsoft, and most other big tech companies go completely nuts. So, you get used to fiddling with languages settings.
I have no idea how we got there, but my guess is that most Google engineers are either : completely ignorant of internationalization issues, don't care, or don't speak more than one language.
PS: Speech recognition, autocorrect, and mobile keyboards : Same problem.
PS2: Apple get it right most of the time.