Translating Bitcoin Core
Bitcoin Core has been fully translated into over two dozen languages, with dozens more languages partially translated—but more help is always needed.
To contribute a translation, create a Transifex account and then go to the Bitcoin Core translation page. From there you can click the Join Team button near the top of the page.
After you’ve joined the team, find the language you want to help translate. Click on it and choose what Bitcoin Core release you want to contribute to.
From the page listing a specific release, you can click the Translate button.
On the Translation screen, click the Untranslated tab. On the left pane will appear the English versions of text that needs translating. On the right pane, you can enter your proposed translation.
After saving your translation, it will be reviewed and (if accepted) included in the next release of that version of Bitcoin Core.
If you have any questions, please contact the translation maintainers listed on Transifex or ask (in English) in the #bitcoin-dev IRC chatroom.