Is there any particular reason that "német" doesn't have to be inflected for plurality, but "szép" does? Does the adjectives-being-plural-if-the-noun-is-plural rule not apply to nationalities?
Adjectives only get pluralized if they're the predicate of a sentence. So, basically, if the adjective is directly before the noun it modifies, it's never plural.
Why is 'a nemet hazak szepek van' incorrect?
The van should not be there.
When we say what something is (noun) or how something is (adjective) in the present tense, don't include van(nak).
On the other hand, when we say where something is, then van(nak) must be present.
Thanks, I got it