[tazjin]

My accept-language header only has en_GB and en in it. Google still randomly serves me pages in Swedish and German (which are both languages I speak, but which I both explicitly disabled in my Google account settings).

The best case of this was when they launched the preview for the new Google Maps version - there was a landing page with some information and a button in the middle. This page was served to me in three languages at the same time (the header, the button and the info text) - presumably served by different internal components that all handle languages differently.