PART 1: Survey of educated Israelis
I got in touch with four very educated Israelis (all have Master's and/or PhD), and this is what they said:
- Israeli #1: daled, yud, and kuf are the common pronunciations, and
dalet, yod, kof are the "correct" ones.
- Israeli #2: daled, yod, kuf are taught in school.
- Israeli #3: daled, yud, and kuf are the common pronunciations, and
dalet, yod, kof are the "correct" ones.
- Israeli #4: "dalet is prescribed by the Academy and is most common, so no question there. The same for kuf. For yud I wasn't able to find the issue addressed by the Academy. They sometimes do that when there is no historic or rule-based reason to favor one form over the other. So I'll go with yud as it's by far more common among native speakers".
Taught-in-school consensus = 3 out of 4 dalet, 3 out of 4 yod, 2 out of 4 kof.
There is a difference of opinion, so clearly it's not 100% obvious. Thus I undertook a second phase of this research.
PART 2: Online research
I did some more research on my own by looking at the Hebrew wikipedia pages on these three letters:
- Dalet (
דל"ת) seems to be the official pronunciation of ד. Interestingly, דל"ד is not even listed as an option on the Hebrew page.
- Yod (
יוֹד) seems to be the official pronunciation of י, and יוּד is listed second.
- Kof (
קוֹף) seems to be the official pronunciation of ק, and קוּף is listed second.
Summary
In summary, it seems that dalet is the least ambiguously most common and correct, thus it is the official one, as well as yod and kof, and these are the "correct" pronunciations taught in school. But many/most commonly say yud and kuf, in addition to dalet. The good news is you can pronounce these three with either variation and no one will blink an eye.