> So what is needed is NLS for TeX and LaTeX.
> For TeX this should be simple; a change file should suffice.
> But for LaTeX? The messages are hardcoded into the kernel... :-(
If you say that the LaTeX messages are hardcoded in the kernel then the
analog of that for TeX is `the messages are hardcoded in the
executable'. Did you try writing a perl or sed script to change the
LaTeX messages before compiling the format file?
> Any chance of having something like this in LaTeX3?
Already some five years ago I guess someone on the LaTeX team (er, me
actually) proposed keeping all the error and help message texts in an
external file and there have been two or three prototype
implementations. Original motivation was not international support: By
not reading the message texts until needed you save a lot of main mem
for normal document runs that don't have any errors.