Google still recognizes my language even when i use VPN addon

When i connect to Germany via Hoxx VPN, google sites still use my language. But this VPN addon works on other sites, e. g. yahoo.com shows everything in german language.

Is there any addon or anything in firefox options or in about:config to disable google spying?

Potentially Google is either using your account language, or if you’re not logged in, your browser language or accept language header, where as Yahoo just uses geo location.

Please invest in an actual legitimate VPN and not one with one of the worst privacy policies I’ve seen.