\begin{center} \begin{minipage}{0.7\textwidth} \selectlanguage{english} \chapter*{Abstract} \blindtext \end{minipage} \end{center} \blankpage \begin{center} \begin{minipage}{0.7\textwidth} \selectlanguage{ngerman} \chapter*{Zusammenfassung} \begin{otherlanguage}{ngerman} \blindtext \end{otherlanguage} \end{minipage} \end{center}