%%
%% The LaTeX Companion, 3ed
%%
%% Example 16-7-32 on page II-561 in "Sentence casing".
%%
%% Copyright (C) 2022 Frank Mittelbach
%%
%% It may be distributed and/or modified under the conditions
%% of the LaTeX Project Public License, either version 1.3c
%% of this license or (at your option) any later version.
%%
%% See https://www.latex-project.org/lppl.txt for details.
%%

\documentclass{tlc3exa}
\pagestyle{empty}
\setcounter{page}{6}
\setlength\textwidth{87.0pt}
%
\setlength\parindent{0pt}
% Use biber program

%StartShownPreambleCommands
\usepackage[ngerman,english]{babel} \usepackage{biblatex}
\usepackage[autostyle]{csquotes}
%StopShownPreambleCommands

\begin{document}
\MakeSentenceCase*{a Story of \emph{Green} and {\emph{Blue}} {Ducks}.}

\selectlanguage{ngerman}
\MakeSentenceCase*{Eine Geschichte \emph{grüner} und {\emph{blauer}}
                   {Enten}.}
Aber \enquote{\MakeSentenceCase{eine Geschichte \ldots}} ist falsch!
\end{document}