It is my intuition, that the origin of the letter y comes from ij based on the usage in Dutch where it very closely resembles ij in both sound and shape. I would go so far as to say it looks like a contraction.
I am particularly interested in this right now, as a company has translated a foreign name into English, and included iy in the name – which strikes me as unusual. If I were transliterating their name, Bafiya seems wrong – and I feel it is better as Bafya or Bafia.
It is hard to justify my opinion, so I was curious about the usage of iy. I can not think of any words that contain iy in them. Are there any?