My name is Eirian and I often get told it is a beautiful name and I do love my name. I pronounce the name slightly more uncommonly but still used. I say ehh-ree-ann. Similar to the pronunciation of the word air at the start and the ending being more like the name Anne instead of un. I think this gives a more feminine feel to it. Strangely with this pronunciation in the Uk, it is spelt wrongly frequently but in Spain and South America, typically spelt right every time after hearing how it is said.
My middle name is Eirian and I've always pronounced it ay-ree-an but apparently it's supposed to be pronounced eye-ree-an. I think the ay is prettier and I've always been that- that is the correct Welsh.