@Oliver Schick is probably getting annoyed at me @-ing him all the time, I just see him as the go-to person for all language based issues (which is a pretty broad remit). Anyway, the Y is not a Y but a thorn, the old English letter for the th sound as often mispronounced in Ye Olde.
I didn't work that out, either, I thought it was meant to stand for 'yobs'.
It's a good job you spelled it 'old English' and not 'Old English'. The Old English letter Þ was only changed to Y by the hand of some scribes after the Old English period.
@Oliver Schick is probably getting annoyed at me @-ing him all the time, I just see him as the go-to person for all language based issues (which is a pretty broad remit). Anyway, the Y is not a Y but a thorn, the old English letter for the th sound as often mispronounced in Ye Olde.