How to change search engine language?
Set yor language by clicking on 'Einstellungen' or navigate directly to the english localized version: http://www.google.com/preferences?hl=en to set it there (you can switch the 'hl=en' for english to hl=hu for hungarian or any other you want in the link). 

Setting your start page is not what you want: This will not affect searches from the widget or from the omnibox (the auto completion, aka instant search).

Edit:
Seems like the keyboard language sets the default... switched from en to german and back.