The History of the Letter ‘Y’
In Latin, the letter “Y’ was named Y Graeca (pronounced ee-grayka) which literally means “Greek Y”. It was named this because the sound it made (“similar to modern German ü or French u”) wasn’t a native sound for Latin speakers. It was usually only used for foreign words.
{in Middle English it was ‘wi’ /wi??/, which through the Great Vowel Shift became the Modern English ‘wy’ /wa??/.} (Source: Wikipedia)