Hi,
The path to the language list is configured in the service "com.adobe.granite.translation.core.impl.TranslationConfigService" and by default the path is /libs/wcm/core/resources/languages.
Since it is not preferred to make changes directly in the libs , you can copy the list from libs to apps and make changes in the list.
Now you can change the list path by going to the url http://<host>:<port>/system/console/configMgr and searching for the service "Translation Integration Framework Mappings" and change the language list path to the new updated list path.
Configuration Screenshot
Hope this helps!
Thank you!
Nupur