Joseph, I’m going based on the words of my Rebbe Muvhak, as well as the sevara pshuta. Wearing pants in public- the Tannaim and Amoraim wore robes. Pants got into fashion in Europe. European custom has been adopted in America, so we wear pants. Pants are not holier than robes, but it’s the minhag.Of course, one should wear something under the robes, but that’s neither here nor there. There are many Afghanis in my area who wear robes instead of pants. Are hoisen now also a mitzvah?
My Rebbe tried to give shiur in English for the benefit of the bochurim, but sometimes he’d lapse into Yiddish.
There are those who gave shiur in Yididsh because that was their natural way of speaking. there are those who give shiur in yiddish because ” it’s amitzvah to speak in yiddish”. Again, vi shteit? Rashi was never mekayeim such a big mitzvah of speaking in yiddish? And if it’s to separate us from the goyim, why not speak Lashon Hakodesh instead of a language that shares linguistic roots with the Nazis yemach shemom?
When the bachurim in Slabodka, the “eim hayeshivos” according to Rav shach, dressed in a modern, stylish manner, were they oveir aveiros? The biggest Gedolim and Roshei Yeshivos all came from Slabodka (Reb Aaron, Reb Yaakov, Rav Shach, Rav Hutner, Rav Ruderman, et al), so it would be hard to say they were avaryonim (transgressors). When a Jew speaks in a refined manner, and dresses in a refined manner, so that all who see him respect him, then he has distinguished himself. When an English-speaking Jew peppers his English with phrases from Gemara and Tanach, then he has distinguished himself. Why the rest has to be German instead of English is something still unexplained, and comparisons to hoisen don’t answer the question.
It’s quite possible when the first European Jews started giving their kids German names like “Freydle”, “Gluckel”, “Berel”, etc, they were oveir an aveira of chukas hagoyim. Now these names are accepted by hundreds of years of use. But don’t tell me they’re holier than names of tzaddikim and tzidkaniyos from Tanach, or similar names in Lashon hakodesh.
In short, whatever reason you have for Yiddish, Lashon hakodesh makes more sense.
Ironic that last year’s much-reviled concert ban was against someone who sang mostly in Yiddish.