\texttt can't show “ij” of babel-dutch' \appendixname in the fonts used bij apa6 man and doc mode

Question

Using the apa6 class with the option man or doc, and using [dutch]babel, \texttt drops the "ij" of \appendixname.

(The Dutch word for "Appendix" (that babel uses) is "Bijlage".

MWE:

%Run with pdflatex
\documentclass[man]{apa6}
\usepackage[dutch]{babel}
\shorttitle{foo}
\begin{document}
\appendixname; \texttt{\appendixname}; \texttt{Bijlage}\par

\renewcommand\appendixname{Bijzonder dit}
\appendixname; \texttt{\appendixname}; \texttt{Bijzonder dit}\par

\renewcommand\appendixname{Bijlage}
\appendixname; \texttt{\appendixname}; \texttt{Bijlage}
\end{document}

Output of MWE:

At first I thought it could be because the "ij" is a ligature, bij after redefining it works fine. This only happens in apa6 class (not jou-mode).

Can someone explain this remarkable behaviour to me?
And, is it a bug?

Answer 1

Your intuition that this is about the ij ligature is correct. If you look at the definition of \appendixname (with \show\appendixname) you'll find that it is

B"ylage

The shorthand "y is \ij{} in text mode, so that you are typesetting

B\ij{}lage

in the first line of your MWE.

The apa6 class loads fontenc with the T1 encoding and lmodern. In the T1 encoding \ij{} is a glyph in its own right and not just a kerned combination of i and j (as it is in OT1: \nobreak\hskip\z@skip i\kern-0.02em j\nobreak\hskip\z@skip). But it seems that the typewriter font of Latin modern does not have the ij-glyph and so you just see nothing in its place.

Depending on your use case you can

• Typeset \appendixname in a font different from \ttfamily.
• Change \appendixname to Bijlage instead of B"ylage.
• Use a typewriter font with the ij glyph.

If you write ij instead of "y/\ij in the rest of your document, the second solution might be the preferable for consistency's sake. You may also want to closely inspect \listfigurename and \listtablename (L"yst vs Lijst) \proofname and \glossaryname. Maybe it would be easier to just redefine \ij then...