What are you on about? Welsh is by no definition "basically considered a dead language" over 30% of the country can speak Welsh. And its on all official communication, like government websites, announcements, road signs etc.

That’s why Welsh and Irish are basically considered dead to many

Uh...no. As far as I know, none of these languages are dead. Irish is dying but it's not dead yet. Welsh is thriving and is pretty much the only Celtic language being passed down the next generation consistently and has a vigorous community with a respectable size.

I think people call languages with very few native speakers "endangered languages".

"the papal city place in Italy" shows how great your knowledge is

A dead language is one which has no native speakers alive to speak it e.g Latin.

Irish and Welsh aren't dead. The only dead Celtic language im aware of (but it has been revived since) is Manx, with the last native speaker dying in the 1970s.

You know there are Welsh schools right? And that the Welsh government has two official languages, Welsh and English? And that all official documents have to be bilingual? I've heard people speaking Welsh to each other in Wales, and I know someone for whom Welsh is their first language.

Does that sound dead?

Technically, Latin is a dead language, but not an extinct language. It could (heavy emphasis on "could") come back all of a sudden. That's what happened to Hebrew.

Extinct languages aren't even spoken by anyone anymore. Not even a single soul. Gone beyond the point of repair. Disappeared for good, like dinosaurs and dodo birds and megalodon.