Does Prismic support non-Western characters?

We do: it's supported, but with certain exceptions.

As long as you use Rich Text fields in Prismic for all text elements, everything will work fine. Note that things might break with the Key Text field, so it's best to avoid it.

Using non-Western characters for media file names might also cause things to go wrong, so we suggest using Latin characters for those.

TLDR: As long as you stick to Rich Text fields for everything text and Latin characters for media asset file names, you'll be able to build a robust project with Prismic.