Problems with diacritics in German keywords

There are some issues with the german keywords.

For example the german word "trauern" (to be sad) is saved as "taürn" (which is not a word in german). maybe you replaced all "ue" with "ü" at some step in the processing?
Other examples are "klaue" => "klaü", "schauen"=>"schaün"

(reported by Kolya Bailly)