A) yekke2, that argument is also faulty because, in part, we didn’t yet have the Torah in Mitzrayim.
(As well, the Nazis YM”Sh also understood Yiddish, so there’s nothing all that muvdal about Yiddish, certainly not all that different than Yeshivish English today.)
Now that, for well over 3,000 years now, the Torah has bound us as one nation, there is no need to resort to speaking our own language as being a Torah Jew does far more for everyone than using a common language.
This is pashut.
For example, if you need a minyan in Paris while waiting for a flight out, no matter what language you speak, the word “Shacharis” and a gesture to your Talis/Tefillin should be enough to convey you’re looking for a minyan and any other Jew will happily join you no matter what language he speaks because we all have the same mitzvos. Again, we did not have that in Mitzrayim.
No Yiddish is needed.
B) ** The following is a quote from another site, if the mods wish to allow it:
If the Mods do not, the following point still stands. **
It’s very insulting and is a lack of derech eretz to many Jews that, in the United States whose national language is American English, one has to publicly Lifnei Am ViEidah “justify” speaking in English, “CH”V”, essentially apologizing for not addressing the gathering in Yiddish; this is a tremendous turn-off and slap in the face to those who do not speak Yiddish, and accomplishes exactly the opposite of what is intended: it alienates those Jews who do not speak Yiddish and erroneously makes some Jews feel superior to those other Jews who do not speak it.
This is not, CH”V, an accusation that all who speak yiddish feel they are superior, but it has certainly happened, and it is a terrible avlah born, most likely, of ignorance as to what being a Torah Jew is really all about.
To be perfectly clear, there is nothing wrong with speaking English, and to apologize for doing so is, again, wrong, despite the good intention in doing so.
Yiddish is useful for only 2 things: historical purposes and for effective communication with the older generation. Everyone should speak English (and/or Yeshivish English), which is an international language, in addition to the native language of the country they live in. This will truly unify all of, rather than alienate, CH”V, any part of, Klal Yisrael.