oh, what a think to ask..

look. yes, when you are a hatchling, you are taught the five vowel, AEIOU and no one teaches a sixth one the vowel Y. they also do not teach anything about W, or Ü. or many other vowels that are distinct, yet mostly esoteric in modern english. the problem with spelling of words, stems from the semmely arbitrary nature of how some letters were chosen or dropped, particularly if it was borrowed from other languages.

why is fantasy spelled with a Y and not with an I or an IE or just an E. (in german for example it is fantase) .

y is a vowel that may be more ambiguous today, than it used to be, having a distinct sound. funny enough, it is based on the greek letter upsilon that is definitely a vowel but sounds like a U. which in turn was burrowed from pheonician waw sound (that letter looks like an i with the dot a bigger circle.

now vowel May serve as consonents, and then require another vowel to designate the movement. (yet, year, foyer, etc). but that does not reduce its definition as a vowel.

incidentally, the only western letter to be employed in Chinese writung is the capital Y or 丫ya. this three-brush stroke, charachrer, is a phonic representation. of the sound ya. but when connected to other.characters is normally something to do with ""girl""