Well, CJK is simply too much for me.
At most, I'd like to support English and Spanish in my game (BTW, an RPG), and maybe an horrendous French translation. Occidental languages. So UTF-16 it's OK for me; even U_ASCII, I think.
I'll try both with std::string<w_char> and a wrapper around Allegro's Unicode routines. Thank you, everybody!
I have another related question: ASCII has 7-bit characters, Allegro's U_ASCII has 8-bit. Are the last 128 characters in U_ASCII the same as in ISO-Latin-1 or does it depends on the locale?
Taking about translation, does anybody know about a good tutorial for gettext?