Grandpa’s funeral was conducted with Ashkenazic Hebrew, and in this particular case (as your correspondent was there) was a certain variety of the Ashkenazic dialect, which prompted the other grandchild to ask about the “oy” sounds.
Interestingly, Ashkenaz (אַשְׁכְּנַז) (Genesis 10:3 shows Ashkenaz as a descendant of Japheth, third son of Noah) is a designation of the first relatively compact area of settlement of Jews in Northwestern Europe, initially on the banks of the Rhine. The term became identified with Germany and German Jews (Ashkenazim), and their descendants in other countries. (There is more to explore here, in future columns.) The term encompasses a whole cultural complex, comprising ideas, ways of life, folk tales, legal concepts, social institutions, and language. The Yiddish language sprang from this culture (out of Middle High German), and evolved through the various meandering travels into different dialects, “borrowing” from various additional languages. Practices and ways of reading and chanting Hebrew also evolved.
The term “Ashkenaz” is used in contradistinction to Sepharad (סְפָרַד - originally in Obadiah 1:20 a location of a colony of exiles from Jerusalem) and the Sephardic Jewish cultural complex emanating from Spain, which also spread and evolved. (We Jews seem never to stop moving.) The Ladino language (a Romance language) derived from this culture and is still sparsely spoken in the Middle East and Africa and elsewhere. (Both languages, Ladino and Yiddish, are written with the Hebrew alphabet.)
When spoken Hebrew was revived in Israel in the early 20th century, the choice was made to pronounce it similarly to Sephardic Hebrew. The non-Orthodox movements began to follow this practice. The most noticeable difference is the pronunciation in Sephardic of bothת and תּ as “t” rather than as in Ashkenazic as “s” and “t.” In some dialects, long “o” sounds may be pronounced as “oy,” which is what the second grandchild heard. The differences are especially noticeable in the Kaddish, which contains a lot of the letter ת (and is written mostly in Aramaic, but that is quite another story).
There are of course other differences. It can be difficult to abandon one dialect for the other, and can take a lot of practice. But it seems worth the work - at least so one’s savs don’t stick out at services.