Hi Sakit,
There are tow components that can internationalized: The identity and oxauth.
1. The identity component ship with an Admin UI containing a toggle button to with language. You can clone the oxtrust project and customized the code to support additional language
1. The oxAuth project don't have a mean to support additional language. If your audience is one language based then you can override the default oxauth.properties file to meet your need.
Now that it is clear, what do you want to achieve?