Quest 4.1 supports languages other than English by creating an LDF file.
I have now added a Quest Translations page to the website containing LDF files contributed by users. Currently we have translations of Quest into German and Spanish.
If you’ve created an LDF file for Quest, I’d love to hear about it! Please email me at alex@axeuk.com if you would like to submit an LDF file to the site.
Games in Spanish
I came across this page of Quest games in Spanish:
http://wiki.caad.es/Categoría:Aventuras_Quest
If you know of any other pages of foreign language games (or indeed any other websites to do with Quest), please let me know and I’ll add a link from this site.