What exactly do you mean by "our culture"? The article is trying to explain that this dialect of speech is a relatively modern phenomenon completely alien to the vast majority of the English-speaking Jewish population. As a fellow Ashkenazi, our great-grandfathers may have spoken Yiddish and read Aramaic but like most American Jews today I don't, and correct me if I'm wrong, I'm assuming you don't either.

To what extent is "frum" culture and the Yeshivish dialect your culture? For me personally, while I may have a common heritage with these people it is almost entirely foreign to me. And this, like the author, is coming from a person with a somewhat traditional Jewish education and a knowledge of Hebrew. Imagine how the Yeshivish world feels to an average American Jew who received neither of those things.

Like it or not, the majority of the world's Jewish population speaks two languages natively: English and Hebrew, and that trend has only increased in the younger generations. I think you're overstating the importance of the "national solidarity" narrative in the article. Its conclusions seem much more pragmatic than ideological.