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.
More discussions about translations may be found in the Translation Discussion and Development forum.
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
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.