We rely on people like yourself to translate ZAP into other languages.
If your language is not available then it means that we, the developers, unfortunately don't speak your language well enough to translate it and no one else has volunteered.
However you can help :)
Get in touch with us if you want to translate ZAP into another language, we'd love to hear from you!
Note that new language files may be available after a new ZAP release has been made available. Check the ZAP Marketplace to see if there is a new version of “Core Language Files” add-on that includes your language.