It's not an answer to why Google is spricht Deutsch to you but at least will hopefully let you change all their services back to English (or ensure they already are in English and stay that way).
Some causes and answers are listed here (basically, English-speaking Google users who don't live in US territory are having problems so most of it does not apply to your situation but at least gives one an idea of show-English-only fixes that are working vs. fixes that are not): https://productforums.google.com/forum/#!msg/websearch/cVE52060AOg/mVIjVvKG2OgJ
Why would it be related to one of your add-ons? Which one?
Ich verstehe nur Bahnhof
Date: 2016-05-10 07:22 am (UTC)From:So I uh, googled, and found this: https://support.google.com/websearch/answer/3333234?hl=en
It's not an answer to why Google is spricht Deutsch to you but at least will hopefully let you change all their services back to English (or ensure they already are in English and stay that way).
If you installed a computer OS with German set as the default, that could be an issue: https://www.quora.com/Why-does-google-display-the-wrong-language-for-me-over-and-over-again
Some causes and answers are listed here (basically, English-speaking Google users who don't live in US territory are having problems so most of it does not apply to your situation but at least gives one an idea of show-English-only fixes that are working vs. fixes that are not): https://productforums.google.com/forum/#!msg/websearch/cVE52060AOg/mVIjVvKG2OgJ
Why would it be related to one of your add-ons? Which one?