This is the case in most European countries:
- Florentine Italian displaced Sardinian, Napolitan, Romanesco, etc.
- Ille-de-france French displaced Provencal, Occitan, Breton, etc.
- English displaced Scots, Gaelic, Welsh, etc.
Even countrires traditionally considered "nation-states" in a linguistic sense such as Portugal went down this route to some degree, with Mirandese and Barranqueno all but gone nowadays.