You need to read some history. The revival of Hebrew as a spoken language did not begin until 1880. For the most part, rabbis learned Hebrew. Ashkenazim spoke Yiddish and the language of their country; Sephardim spoke Ladino and the language of their country.

Even in Israel today, there are separate chief rabbis for the different groups. Really, Jews are not clones, though identitarian Jews love to pretend they are.