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Sure! This is a wiser approach than inventing translations on your own. Beside asking native speakers, the ideal is to check other software projects and how they translate technical terms, if you can find some such projects.

Now i have translated the 500 most used expressions, can we go the next step now? Thank u!

Sure, the next step is translating the rest of the core messages: translating all of them makes a fully functional basic MediaWiki (without extensions). I don't remember what's the exact percentage of core messages which needs to be translated before the language is enabled on MediaWiki, the point is that even after that you have to know that more work is needed; ask the staff on Support to add it to exported languages, siebrand or Raymond will answer you soon (but they're very busy these days).