The history here is more complex than that… originally Irish was not an EU language because Ireland just used English… then as part of one the cycles of EU treaty renegotiation, Ireland successfully pushed for it to be made a secondary EU language… and then later successfully pushed for it to be upgraded to full status… so Ireland actually has two EU languages, their original one (English) and their newer one (Irish). Because the practical reality is everyone in Ireland is fluent in English-around 60% of Irish people can’t even speak basic Irish, and fluent Irish speakers is <10% of the population

Also, English remains one of the main working languages of the EU bureaucracy, because for many EU states (especially in Eastern Europe) it is a more popular foreign language than the other two (French and German)-when Czech diplomats need to talk to Spanish diplomats, English is the language they choose.

This idea people have here that “each country gets to nominate a language” isn’t how it actually works. The treaties just contain a list of languages, and which languages are in the list is down to diplomatic negotiations not any coherent principle.