Both this site and translate.wordpress.org are powered by GlotPress, a freely available tool enabling collaborative translation. Below are some basic instructions showing you how to select your language and submit a translation.
We will be submitting a Spanish translation in this example. These screenshots are taken from translate.wordpress.org and may vary slightly compared to this site (and should they update it in the future), but the principle of submitting translations remains the same.
1. Register and log in to the site you want to contribute, as per our getting started instructions.
2. Visit the relevant translation project from our project list.
2.1. If translating on translate.wordpress.org, we always suggest you translate the Dev version.
3. Find the language you’d like to translate from the list, and click on the language name. If it doesn’t exist, please let us know.
4. Click on the ‘Untranslated’ link at the top of the page to show untranslated strings.
5. Double click on a translation you’d like to add or suggest an edit, or click the ‘details’ link.
6. Enter your translation, then click “Suggest new translation”
7. Your translation is now awaiting approval from an editor, and the next string for translation is automatically opened.
8. That’s it! If you’d like to become an editor for your language so that you can approve others’ translations, please see our ‘Becoming an Editor’ instructions.
Further instructions can also be found on the WordPress translator handbook.