WinnieThePooh,
Excellent point!
As I once pointed out to Joseph (who thinks Yiddish is STILL the most spoken Haredi language).
Unlike 30 yrs ago, try asking directions any random Charedi, Chassidic, Chazon Ishnik, Ponovich etc. in Bnei Brak and in even most Yerushalmi neighborhoods in Yiddish, they won’t understand a word and even if they will understand some, they won’t be able to respond, I’m not even going into S’phardim.
So in other words, most Klal Yisrael communicates or understands in ‘Hebrew/ Ivrit.
And thus, whatever Rav Ahron Kotler said (if true) is definitely not relevant today.