The answer to the frequently posed question as to whether Y is a vowel (under which this writeup once resided) is of course mu or possibly null. The question results from the confusion between two different classes of entity: the alphabetical characters of written language, and the human sounds of spoken language (phonemes or phones, doesn't really make much odds for the purposes of this diatribe). The distinction between vowels and consonants lies in the manner in which the sounds are produced by the human body (without or with the addition of friction in the breathing tract); this does not apply to "Y" which is produced with a stick in the sand, a Mont Blanc or as ASCII character 89, no breathing required.
The use of "Y" and letter combinations including "Y" in various alphabetical writing systems that use the Latin alphabet is an indicator - with varying degrees of strictness, English being one of the less tightly mapped - of the use of various phonemes. Quite a lot of them are vowels. Some aren't. Even in languages where, in the normal orthography, "Y" is used to indicate a vowel sound, it is unlikely that it does so when their speakers talk about New York, while in other symbolic uses (y=x2) the letter does not have a vocalic sound as a referent.
Nonetheless, it is unarguably true that in the International Phonetic Alphabet, the symbol y does indeed represent a vowel, and only ever a vowel (the vowel sound in French une, German für, Swedish ny, etc.)