I've just try this:
- I've downloaded and installed Might and Magic 6 pack from gog.
- I've resumed my original (1998) italian cd version of Might and Magic 6, that didn't work in Windows 7.
- I've overwritten the "data" folder of installed MMVI with ones from italian CD.
AND IT SEEMS TO WORK PERFECTLY!!!
I've just mantained the voices in english, because the italian localization is not so good.
Someone could try this with other languages, replying to this post to collect our results?

Czech version works fine. Though, that translation was installed via installer and not by copying data files (the game was not released here fully translated, the translation was done later).

Veramente il parlato in italiano di M&M6 è decisamente migliore di molte altre produzioni moderne (per esempio il parlato di HL2).
Hai provato ad installare la patch 1.10?Funziona tutto correttamente?

The Italian voiceover of M&M6 is superior than a lot of modern AAA title (HL2 for esample).
Have you tried to install the 1.10 patch?It works?