Yup, it's a -my sound in Welsh - like Dai. There are Valmays and Valmaes and Falmais here too, but nowhere near as many and Valmai was the first version to appear, so I'm assuming it was the original. The first three were born in 1899, and nearly 600 of them in the following 40 years - quite a lot for an unusual name. They were mostly born in Wales, but there are quite a few elsewhere too. I keep thinking it must have been in a popular song, or something - but popular enough to spawn Valmais thousands of miles away, and yet completely unheard of now? Maybe not.