Zahavasdad………..
Things change over time. The postwar baby boom is over. When mys siblings and I went to school in New Haven, both Hebrew and Yiddish were offered along with 10 other foreign languages. Now there is Spanish and Chinese.
As for those who write about prewar Yiddish and post war Yiddish. 90% of the Yiddish I use is with people speaking the former and whatever reading is of classic material, not modern Jargon.
I learned Yiddish for business purposes. My father was in the clothing business and it was useful for buying trips in NYC. Our family having arrived in the USA in the late 1860s from Suwalki and took academics in the public high school afternoons. Hebrew and Yiddish assured that 2 of 4 classes were all yidden.