quoting dhok, Deacon:

quoting meficat, Cool Cat:

quoting dhok, Eques:

Newest pet peeve: library staffers who can't tell the difference between Spanish and Portuguese.

What about telling apart Castilian Spanish and Catalan?

Catalan doesn't do final -o on its masculine nouns, has <ç>, and doesn't break VL *ɛ ɔ.

The Romance languages are pretty easy to tell apart, honestly. I think something like Danish vs. Norwegian would be harder than any of the Romance pairings, and if you wanted to tell, say, Arabic from Persian you'd need a crash course in an entirely new alphabet.

It's easy to tell Nynorsk from Danish/Bokmal since it has <ei> everywhere, but I don't know if there's a way to tell Danish and Bokmal apart.