Y-
The letter "y", like "w" (w-), is not considered an initial in pinyin. Why?
There are two main cases where the letter "y" is used, and in neither case does it represent a unique sound:
Case #1: "y" replaces "i"
When a syllable has no initial (linguists call this the "zero initial") and the first letter is "i", it gets changed to a "y":
- ya: "y" replaces the "i" in -ia
- yan: "y" replaces the "i" in -ian
- ye: "y" replaces the "i" in -ie
- yin: "y" replaces the "i" in -in
- yong: "y" replaces the "i" in -iong
Case #2: "yu" replaces "ü"
When a syllable has no initial (linguists call this the "zero initial") and the first letter is "ü", it gets changed to a "yu":
- yuan: "yu" replaces the "ü" in -üan
- yue: "yu" replaces the "ü" in -üe
- yun: "yu" replaces the "ü" in -ün
Why do these? Because it would make pinyin a lot harder to read a lot of the time. So the "y" makes it much easier to pick out syllables when there is a cluster of vowels in a word.
Case #3: "y" starts the syllable
When -u has no initial (linguists call this the "zero initial"), a "w" gets added on to the front of the syllable:
This is done for the same reasons as Case #1 above.