I'm looking at you Google as the worst offender. I swear that some developers have never left the US.
Geo location != preferred language.
Accept-Language header in my browser is telling you what I want. Listen to it.
It's just like with Windows, applications use the location instead of the OS language to chose what language to default to.
L10n is broken. And no one seems to have any real interest in fixing it. The tools are there but they get ignored by pretty much everyone.
Stuff like .../?hl=en may help indeed (but it has to be put manually.
My Firefox sends the following Accept-Language: "en-us,en;q=0.8,sv-se;q=0.5,sv;q=0.3".
When I go to Google.com in a new private browsing context, I am redirected to Google.se with English language. When I go straight to Google.se in a new private browsing context, the page is in English.
Ads though. Still in German. Not sure if that is a good thing or a bad thing. I'm even more blind to them in the wrong language. I guess that is a good thing!
As someone living in the US who speaks English and Japanese, I often get annoyed by the fact changing the language would affect feature set to match the language and vice-versa. I almost want something like ja-US and en-JP!
(I assume it stands for "No Country Recognition" but I'm unsure of that). Visit it once and I believe it stores a permanent cookie on your computer telling google not to re-direct you to a country specific site.
Been using it for about 10yrs now as it annoys me when I get re-directed when accessing sites over a vpn.