The "ow" in "cow" is a digraph: two letters used to represent one sound. Oh, thank you for saying that! I was struggling and struggling to try and discern any sound for w in that word.

I was thinking the other day about the w in why, and realized that for me at least it's a diphthong: kind of an ooo-wuh, the whole being sort of like ooo-wuh-eye. Hmm--correction--more like ooo-wuh-eye-ee. Not quite Hawaii! smile