In the following document
\documentclass{article}
%\usepackage[german]{babel} % also try english, ngerman and dutch
\usepackage{listings}
\begin{document}
\thispagestyle{empty}
\begin{minipage}{1em}
und/oder % and/or on german; shouldn't be hyphenated
\medskip
n und/oder % same es above, but not the first word in paragraph
\medskip
und/""oder % "" is a shorthand in some languages, provided by babel. It allows a linebreak without hyphen
\end{minipage}
\end{document}
I get problems with the hyphenation. As soon as both packages are loaded—the order doesn't matter—the /
seems to be treated as ordinary letter, at least if certain languages are activated (e.g. german, ngerman or dutch). Only loading these languages, but not activate them, has no effect. Normally, the whole term und/oder
shouldn't be hyphenated. Interestingly, even pdflatex and lualatex produce different results: lualatex hyphenates the first word of a paragraph (compare the first and second row in the images).
Does anyone know what's the reason for this? I haven't noticed this behaviour before and I'm using both packages in nearly every document. Results of several combinations below.