u/WerewolfGullible1056

Hi! I want to learn Yiddish for my studies on the rise of Zionism between the mid-nineteenth and early-twentieth centuries. I started learning Yiddish on Mango Languages, but I wasn't sure if it was the best approach, especially since I read that Modern Hebrew has influenced how Yiddish is spoken today. Are there considerable differences between modern Yiddish and Yiddish before the formation of Israel and the consequent growth of Modern Hebrew?

If it has changed substantially, does anybody have any recommendations for learning Yiddish as it would have been written/spoken in the 19th century until before World War 2?

A groysen dank!