Historically, we've seen the larger languages build themselves up by intentionally stamping out the teaching / use of smaller local languages. France banned some regional languages from appearing on broadcast television for years, and etc.
This might be required to get full buy in for a unified language, which is a bit sad but makes some sense - if you ensure it's taking up more and more of media and culture more people know it from immersion, and other languages are reduced to being spoken at home / with friends and that's going to cut into how many people really are fluent in them.