Does Diablo 2 Resurrected support any other languages?

Yes. They are adding five 'new languages' - we don't know what they are yet.
The original game already had English, Spanish, German, French, Portuguese, Italian, Japanese, Korean, Chinese, Polish, and Russian.

Blizzard wrote:

We added five more languages. So that's a feature to lots of other people who speak those languages.

Rob Gallerani - Lead Designer 27:05 19th Feb 2021