I was at an Ashkenazi beith kneseth this past shabboth and noticed that they didn't distinctly pronounce their Shuruq's and Hholam's and instead substituted them with Hhireq's. I'm not sure if it was in all cases, since I only noticed it come up with a few words. The examples I remember are:
- Sidur = Sidir
- Qidush = Qidish
- Yom Kipur = Yom Kipir
- Kashruth = Kashris
- Sukoth = Sukis
- Parshoth = Parshis
Whats the source for this practice?
Do all cultural groups of Ashkenaz usually pronounce in this way? I believe the congregation was mainly Hungarian and Polish (if that makes a difference).
Also, if it isn't for all words that those two vowel sounds change, then what's the grammatical rule to know when you pronounce which sound when?