ZD,
1. Regarding the Septuagint, the point is that it did not make Greek holy (and BTW, the lingua franca of the roman Middle East was not classical Greek but Koine Greek).
2. The takkana to use Yiddish was a response to the Neolog (Reform) who were, as they said, more Hungarian than the Hungarians. BTW, the bachurim in Pressburg earned an external academic diploma in return for a draft exemption as theological students. This stood the Orthodox in good stead when Franz Josef was forced to sign a compromise with the Hungarians that included him speaking in Hungarian, which is an extremely difficult language, while in Hungary. The head of the Neologs spoke to him in literary Hungarian, which annoyed him very much. When the Chief Rabbi, Rav Koppel Weiss, first met him the Emperor started to rattle off his prepared speech when the rabbi interrupted him and told him in perfect German that he did not understand Hungarian. FJ patted him on the shoulder and said “We are two old gentlemen. We will never learn this language”.
Ubi, the first generation to grow up in America also did not use Yiddish in their daily lives except for a word here and there. In any case, Yiddish was certainly not spoken by Sephardim (who mainly spoke Ladino) or the Eidot haMizrach (Judeo-Arabic). Yiddish is simply a dialect of German. in fact, I have a friend whose wife is from Switzerland. She told me that Yiddish is close enough to Swiss-German that she can understand it if the person speaks slowly.