Emily Dickinson Lexicon

Y,

the twenty-fifth letter of the English Alphabet, is taken from the Greek υ. At the beginning of words, it is called an articulation or consonant, and with some propriety perhaps, as it brings the root of the tongue in close contact with the lower part of the palate, and nearly in the position to which the close g brings it. Hence it has happened that in a great number of words, g has been changed into y, as the Sax. gear, into year; geornian, into yearn; gyllan, into yell; gealew, into yellow. In the middle and at the end of words, y is precisely the same as i. It is sounded as i long, when accented, as in defy, rely; and as i short, when unaccented, as in vanity, glory, synonymous. This latter sound is a vowel. At the beginning of words, y answers to the German and Dutch j. Y, as a numeral, stands for 150, and with a dash over it, Ȳ, for 150,000.