In a second hand bookstore in Tel Aviv I found a Yiddish-language book from 1923, apparently written for Yiddish-language Hebrew teachers. It contains stories that explain Hebrew words and concepts in Yiddish. It's the third part of a series. Unfortunately I couldn't find the first two parts.
However the book found its way to Eretz Israel, I don't know.
A great ocean
A clever answer
Why is the water in the ocean salty? A father has asked his little son one time.
I think, daddy, that is so because, the son has answered, there is a large number of herring there.
(The Hebrew word for herring translates to "salty fish".)