How to train bilingual models?

In language_modeling examples, there is an script to train a T5 model for a language. I would like to know how can I use or change this script to train a bilingual language for X and Y languages? Is it possible to do if via this code?

Also I would like to know if it’s possible to initialize training from a multilingual model like mt5, and then use training data for one or two languages for further training?