Oh, that's interesting - I've played the Polish bit from the examples page [1] and it's quite heavily accented. Like a foreign national learning the language. Do the other non-English examples also sound somewhat off to native speakers?
It's just a characteristic of some of the default voices. I made some perfect French voices by having somebody on Discord check for native accents, because otherwise I can't tell. Once somebody does this for every language it should be all set. (Somebody who isn't me though, it takes awhile and I'm just playing around a bit, don't even have a use case for TTS honestly.)
The french example sounds off in my opinion, it seems to mix up its consonants/ vowels.
The "OU" sound from "nous" sounds like "EU", or like if the sound was skipped.
The "OH" sound from "sommes" sounds like "EU" (again, but less pronounced).
The "T" sound from "trop" becames "P" ("pro").
[1] https://suno-ai.notion.site/Bark-Examples-5edae8b02a604b54a4...