I love history. One of the things that fascinates me about history is the way it is layered. Imagine if you photographed the view outside your front door every minute for an entire day. With nearly 1500 photographs, some would look exactly the same, but if you lay them out next to each other you'd see the changes in the view from your front door. In this frame there is a man that wasn't there, in that frame its late afternoon etc. That's like a tiny microcosm of the layers of history.
What also fascinates me is the layers that develop in things like language, in this case, Hebrew as spoken in the lands of Ashkenaz. Ashkenazic Hebrew gets no respect. It was rejected by early Reformers, maskilim and Zionists as a ghetto pronunciation(s), a Eurofied shprache that removed the Semitic character of Hebrew (and by extension, Aramaic pronunciation). I'm not going to comment on that, but I find the layers in Hebrew Ashkenaz to be worth noting.
For starters, there is a great deal of evidence that Hebrew was voiced in Ashkenaz much like that of the Sephardim until the 14th century. For example, they did not distinguish between kamatz and patah or tzere and segol (albeit in the opposite way that the modern Chassidic pronunciation doesn't make the distinction). This is attested to by Ashkenazi grammarians, like Yekusiel of Prague, as well as the massive confounding of those nekudos in many pointed manuscripts from Ashkenaz.
An interesting historical point was how the pronunciation of the letter ח (hes, spelled חית) came to be pronounced in Ashkenaz. By midieval times it had lost its Semitic character, but in the two great Ashkenazic communities it came to be pronounced differently. In the one, that of the Rhineland in the West (called at the time Shu"m, after Speyers, Worms and Mayence), the sound had migrated toward that of H. In the other community, that of Rothenberg, Nuremberg and Prague, it had come to be pronounced with the familiar Asheknazi way, like the "ch" in "Bach". As a result, the Eastern Ashkenazim made fun of their Western brethren, calling them בני הית (Benei Hes). The Westerners countered by referring to the Easterners as בני כית (Benei Khes) as if to say, "Hey buddies, a ח isn't a ה, granted, but it ain't a כ either." This was, of course, a sly reference to the Children of Heth, in Gen. 23. Midieval humor; gotta love it.
It should be noted that there is sometimes a difference between the formal and popular pronunciations, and sometimes this difference preserves something interesting, a residue of an earlier Ashkenazic pronunciation. When reading the Torah (formal) people will usually read carefully and literally according to the vowels but modify them informally, as in when studying Torah. An example of this is how the word דם "dam" (blood) is pronounced. It is written with a kamatz and should logically be read as "dum" (or "dawm")--and when reading the Torah it invariably will be, as it will when the list of plagues at the seder is recited. But popularly it will invariably be pronounced as "dam", as if there is a patah. That's a left-over from long ago. Another example is Jerusalem; formally pronounced as Yerusholoyim but popularly almost always as Yerushalayim.
A well known example of a residue is the name "Yankev" for Ya'akov, which preserves a remnant of the Semitic pronunciation of the consonant ע, long lost among Ashkenazim. An interesting example is how the fourth letter of the Aleph-Bet, the ד (daled) is pronounced. As a child I could not figure out why it was spelled דלת (dales) yet pronounced daled. It is, of course, the remnant of the earlier dalet, only it migrated toward daled instead of dales (although the 18th century Bibliophilus dictionary has dales).
Finally, a note about the changed shuruq/ kibutz (u, oo) toward "i", present today among Chassidim mainly. As early as the 16th century this was remarked on, by the Maharal among others. Some defended it, as it originally preserved a distinction between the shuruq and the shorter kibutz, others were appalled by it as a corruption. Be that as it may, its interesting that in some cases, even among those who pronounced it as "i" they made one exception: for the word רוח (ruach, riach). In Yiddish, "riach" is a curse word, as in a riach in zayn tatn, "Damn his father." When the Torah was read רוח would be pronounced "ruach", which is evidence of a self-awareness that is probably since lost.
In the main, most of this info is from The Phonology of Ashkenaz by Dovid Katz.
On the Main Line, now with tags: Hebrew