I heard Huw Stephens on the radio say “a mae” last week. It sounded really odd. I think he started saying one thing, changed his mind, and ended up saying something else, so he produced this really unnatural-sounding sentence.
The pronunciation of “ac” as “ag” is something which is as at least as often honoured in its breach as is it is in its observance- at least by my experience! (And I’m someone who would say you can notice the difference in pronunciation.)
Funnily enough, had a conversation with a couple of people who make/did make a living through writing in the Welsh language the other day about whether they would use “ac Ianto” or “a Ianto”. Both said they would be likely to say “a Ianto”, even if technically it “should” be “ac Ianto”.
[I assure you that the majority of my conversations are more interesting than this! It was about the right thing to put on a birthday card ]
I get the feeling that the use of “ac” or “a” before consonantal “i” or “w” is a matter of personal taste - but again, just my experience!
Though in English it is pretty cut and dried- you use “a” before a consonantal “i” or “w” sound, and “an” before a vowel “i” or “w” sound [a young man, an evil hamster; a well trodden path, an oozing sore], in Welsh whether you use “ac” or “a” before the consonantal forms tends not to be so cut and dried- at least in speech. Though officially it may tend to “the other way round” than in English, it seems pretty much left up to the individual.
When I first saw that I thought wouldn’t “a Ianto” be a bit odd, but that was seeing it in isolation. Then when you construct a sentence using it and compare say Bethan a Ianto to Bethan ac Ianto and suddenly my brain goes into a spin and now I think I understand where you are coming from. Somehow Bethan a Ianto sounds better, but I’m not a native Welsh speaker and I’d love to know what’s what here.
The choice of a or ac actually influences the pronunciation of the subsequent word. And maybe the pronunciation of that word influences and reinforces the choice of a or ac: a ianto comes out as a yanto, whiile ac ianto sounds more like ac ee-anto. Which is the chicken and which is the egg here is difficult to say and maybe irrelevant.
Compare also yr iaith Cymraeg ( yrr ee-ayeth ) and y iaith Cymraeg ( uh yayeth ). The former in particular becomes more of a vowel the more you rrrroll the r in my experience!
Excuse my poor attempts at writing phonetically, by the way.