How implement Multilanguage site with react typescript from backend Flask?

  flask, postgresql, python, reactjs, typescript

I have a web app where when the user start the signup process will select the language and also this can be modified in the options settings and that data is already stored in the database with PostgreSQL, the question is what is the best approach to set the language changes over the react typescript frontend from the flask backend? and how can I implement it? now will start with 2 languages but in the future, I will add more languages, any suggestion, library, or idea can be good.

Thanks in advance,

Source: Python Questions