Translations, also known as language packs or languages are available to translate the MyBB interface into another language. All of the text that MyBB generates (besides user-inputted messages), are translatable.
Each board comes with the English language pack by default. It is recommended that you do not delete this language pack.
Finding Translations
The complete translations that have been submitted to the MyBB Group are listed on the MyBB Mods website and can also be found in the Translation Releases forum.
More discussions about translations may be found in the Translation Discussion and Development forum.
Installing Translations
There are usually two main components of installing a language. Firstly, the language files need to be uploaded. Secondly, the translated image files (should they exist) need to be uploaded.
Uploading the Language Files
The language files should be uploaded to the inc/languages/<language name>/ folder. The translation author should give you instructions via his or her readme on details including what the <language name> folder name should be.
Uploading the Image Files
If these exist, they should be uploaded to images/<language name>/ and groupimages/<language name>/. Again, the translation author should have given you more detailed instructions in his or her readme file.
Finishing Touches
Go to User CP > Edit Options. You should see the translation in the Other Options menu. Try out the new translation and make sure that everything works.
Default forum translation
If you want your new translation to be default for all new users and guests you can change it by going to Admin CP > Configuration > Change Settings > General Configuration > Default Language. This would make this the default translation for all new users and guests.
Please note: Changing this in the Admin CP will not force a new default translation for existing users on the forum. They will need to change it manually in their profiles.
Default translation for Admin CP
You can set the default Admin CP language to be different than the default forums translation. To do that you should go to Admin CP > Home > Preferences > Admin Control Panel Language
Note that you have the options Default and languages installed on your board. Option Default will make the default Admin CP translation the same as the forum translation.