Earlier quoted context omitted.
> It’s fascinating still to read, for example, Hertzl’s (Sephardi on his fathers’s side) commentary about this specific issue. I personally wouldn't take my source of knowledge about Yiddish from father of the movement whose whole ambition was to abandon the Yiddish world. > To be accurate, Ashkenazi jews don’t speak Yiddish they speak German. There was a cultural disconnect between these two groups themselves. The t…
Eastern-European, not Ashkenazi. Ashkenazi is associated with German, secular Jews, emancipated and mostly assimilated already by the end of the 19th century. Eastern-Europeans are neither of that and BTW, using religious study as "education" is misleading. In the modern world Hasidim and Haredim are not very different from the Taliban (including their objection to education of girls). There are exceptions of course,…
The European components (called, in Israeli discource, Ashkenazi) of the secular Israeli mainstream overwhelmingly trace their roots to Eastern Europe; Ben Gurion was born in Poland, Dayan's parents were from Ukraine, and the fathers of both Tzipi Livni and Bibi Netanyahu were born in Poland.
As Eastern European Jews secularized, many of them began to use non-Jewish languages for secular literature, while others (notably the more nationalist or socialist ones, e.g. the Bund or the Folkists) began using Yiddish as a secular language. However, those who went to Israel used Hebrew for these purposes, and those who stayed in Europe were killed.
Generally, it sounds like you're working under the misconception that the ultra-Orthodox and National Religious [1] are ethnically different from European-descended secular Israelis. They are not. They are distinguished by the ideological leanings of their grandparents in the early-20th-century, after which point individuals moving between the blocs became less and less frequent (though not unheard of).
[1] Very different groups, by the way - the National Religious uniformly speak Hebrew, and are most of the religious people in the settlements you're talking about.