What two countries in Europe speak the same language?

There are several pairs of countries in Europe that speak the same language, here are a few examples:

* Belgium and the Netherlands both speak Dutch.

* Austria and Germany both speak German (though with some regional variations).

* Switzerland and Liechtenstein both speak German, but Switzerland also has French, Italian, and Romansh as official languages.

* Ireland and Northern Ireland (part of the UK) both speak English.

Do you have a specific language in mind?