All religious texts are written in Hebrew which means many Jews know the Hebrew alphabet and how to read it
Excellent, but the point is that the Ashkenazi Jews did not speak Hebrew, contrary to your false claim, but Yiddish, which is a non-Semitic language. It’s theoretically impossible for a Semitic tribe to completely stop speaking their own language for some reason and instead start using a non-Semitic language, unless, as in the case of the Ashkenazi Jews, they were never a Semitic tribe but something else entirely…