将部分内容翻译成德语

Question

这是我的代码：

%% Packages
%% ========

%% Babel provides support for languages.  'english' uses British
%% English hyphenation and text snippets like "Figure" and
%% "Theorem". Use the option 'ngerman' if your document is in German.
%% Use 'american' for American English.  Note that if you change this,
%% the next LaTeX run may show spurious errors.  Simply run it again.
%% If they persist, remove the .aux file and try again.
\usepackage[ngerman]{babel}
 \addto\captionsngerman{% 
  \def\abstractname{Abstract}%
  }
%% Some other packages

%% Document information
%% ====================

%% Some other formats

\input{sections/0_abstract}


\input{sections/acro}
{
    \linespread{0.7}\selectfont{}
    \glsnogroupskiptrue
    \printglossary[type=\acronymtype]
}
\printglossary

\input{sections/1_introduction}
\input{sections/2_analyse_of_project}
\input{sections/3_conceptplaning}
\input{sections/4_controller_implementation}
\input{sections/5_controller_testing}
\input{sections/6_evaluation_and_result}
\input{sections/7_summary_conclusion}

\appendix
\input{sections/a_appendix}
\backmatter

\bibliographystyle{plain}
\typeout{}
\bibliography{./sections/bibliography.bib}

\end{document}

我的一个部分是

\chapter{Konzept}
\section{Regelstrecke und Modellierung der Gleichstromantriebs}
\subsection{Regelstrecke}
\acrshort{iso}11898 es beschreibt einen physikalischen datenlink...

我的问题是，我的部分是德语而不是英语，所以我的文本带有红色下划线。我该如何改变这种情况？