If Yiddish is holy because so much Torah was learned in it, then French is holy because Rashi and many Provencal rishonim learned in it, and Spanish is holy because many Sefardi rishonim learned in it, and of course Arabic, a real loshon hakodeh and the original language for Moreh Nevuchim and Peirush Hamishnayos lehaRamba”m. And don’t forget the ima delishnaos, aramaic, the language of our Tannaim, Amoraim, Savoraim and Geonim! And that means English is a Lashon Hakodesh, the native language of Lakewood ir haTorah, or at least the yeshivish jargon of it. And yet Rabbi Yehuda Hanassi disparaged Aramaic, despite all the Torah learned in that language. What did he know that today’s Yiddish lobbyists do not?
Finally, chanoch lenaar al pi darko means that teaching kids in Yiddish is bittul Torah if they don’t understand it.
When I was in first grade, I attended a “cheder”-type school where I read the passuk with the yiddish teitch. As someone who didn’t speak a word of yiddish, I accomplished NOTHING. I recently spoke to the best guy in the class. He told me that he parroted the yiddish but didn’t understand it either. So my limud torah was sacrificed on the mizbeiach of Yiddish. My Torah says limud torah is important, but does not mention Yiddish as a mitzvah. This beatification of Yiddish is just one more atzas hayetzer to ensure that many people don’t actually learn Torah, and have to ganven to make a parnassah since they can’t communicate in the lashon hamedina. The Gedolim were in favor of teaching kids in the language in which they learn best. Daas chachomim hepech midaas baalabatim.
I do advocate learning Yiddish as a practical matter as a “hechsher mitzvah” to attend the top shiurim in Eretz Yisroel, but it’s not a mitzvah bifnei atzmah. Rabbi Eliezer (who held that even a hechsher mitzvah is doche Shabbos) is a daas Yachid.
Yiddish is given so much attention today because it makes people who speak Yiddish feel that they are mikayem a mitzvah by speaking Yiddish, and haosek bemitzvah pattur min hamitzvah. But as a litvak, I have yet to see a real mekor for the idea many would have you believe that redden mikveh neias in Yiddish is a bigger mitzvah than learning Torah in English.