I propose adding a simple text translation. I.e. a game text passes a text substitution filter (which gets native language text from separate files) then it is put on the screen in user's native language.
Technically best solution would be (IMHO) gettext, as there're dozens of tools for translating/merging etc.
That would hopefully thrust fans to translate games because they don't need to hack data files anymore.
Appears to be not as simple. The text is dynamically generated (mostly) hence pure gettext is inappropriate. A lot of work is required, as I was told.