You’ll have to take this lady’s claims with a grain of salt, but at least she seems to have learned Yiddish well.
I don’t know where this post belongs but somebody will soon throw it into conspiracy, so it doesn’t matter.
Yiddish consists of words derived from German and Hebrew, 80% and 10% respectively, but pronounced quite differently and the rest from the local language. Thus, Yiddish spoken in America has many English words and Yiddish spoken in Argentina has Spanish words, etc.
In Israel I went to a Yiddish theater near Tel Aviv with a German roommate. People looked at us funny and asked us if we would understand the piece, but we had no problem understanding. It wasn’t a sophisticated play, but a light musical comedy anyway. It was quite enjoyable.
There are different varieties of Yiddish spoken within Brooklyn and this is due to religious reasons.