soul package does not work with user-defined language shorthands

Question

Using \caps from the soul package with user-defined language shorthands generates an error. However, it works fine with language shorthands defined by babel itself, e.g. by using \usepackage[ngerman]{babel}.

Example:

\documentclass{article}
\usepackage[english]{babel} 
\useshorthands{"}
\defineshorthand{"~}{\textormath{\leavevmode\hbox{-}}{-}}
\usepackage{soul} 

\begin{document}
    \caps{LS"~2}
\end{document}

Answer 1

soul performs a little test to see if the german language has been loaded, so that the shorthand " is taken into account when parsing the string. Just add to the preamble:

\newcommand{\mdqoff}{}