Hebrew vs. Yiddish

They are related, but they are separate languages. Hebrew is the more historical and traditional of the two. Yiddish is sort of a regional dialect/creole of Hebrew.

Yiddish was spoken by European Jews. It’s a mixture of Hebrew, German, and other Eastern European languages. Hebrew is a language born in the Middle East, long before Jews migrated to Europe (the Ashkenazi). Many American Jews will speak Yiddish, since they migrated from Europe (not from Israel).

Both languages use the Hebrew alphabet in written form.

Sources vary, but there are between 5x and 10x as many Hebrew speakers than Yiddish speakers. There was a vast decline in Yiddish speakers after the Holocaust of World War 2.

Many European Jews speak both languages.