Even if yiddish was the langauge that the most torah was learnt in (I’d think that would be hebrew/aramaic, but OK), and even if every single jew only spoke yiddish, how would this give it kedushah?
Joseph, even if ivrit was created soley by apicursis(es? How do I say this in plural?), why would it be tumay? It is still based on Lashon Hakodesh, and still has quite a few words that are exactly the same. Do those words have kedushah, and the ‘new’ words tumah? And I’d assume that a significant amount of Torah has been learnt in Israel in ivrit, so by your logic it should be kudosh! (Along with english, french, spanish, roman, and the language of every other country that jews have ever lived in.)