How do I get LibreOffice to use English words in dialog boxes?
There was bug tdf#104547. It occurred when setting UI to English coming from a different language. It was reported (RESOLVED WORKSFORME) to no longer live in V6.0.0.2 (and higher, hopefully). I was affected myself and did not yet have the issue again when using V6.0.0.3. I think the user profile was cleaned up.