I also had many problems with the title page in my thesis 'cause it wasn't exactly the format what I wanted and I needed some additional items on it. I solved the problem by making my own page in a separate file and including it into my document. I explained it here yesterday: http://tex.stackexchange.com/a/207949/63764

Maybe it will work for you if you make 2 title pages. germantitle.tex and englishtitle.tex and include them both into your main document.

I also had many problems with the title page in my thesis 'cause it wasn't exactly the format what I wanted and I needed some additional items on it. I solved the problem by making my own page in a separate file and including it into my document. I explained it here yesterday: https://tex.stackexchange.com/a/207949/63764

Maybe it will work for you if you make 2 title pages. germantitle.tex and englishtitle.tex and include them both into your main document.