Don't worry about Hefin just yet!
priodi - marrying/to marry
priodi â - marrying to/to get married to
Mae Alys, sy'n gweithio fel cofrestrydd, yn priodi Gareth a Sioned heddiw. - Alys, who works as a registrar, is marrying Gareth and Sioned today.
If Alys was getting married to Gareth, then the sentence would be:
- Mae Alys yn priodi â Gareth heddiw, and then Hefin might justifiably be a bit upset.
Who knows! In informal language quite a few things that 'should' be there can get dropped, especially because the context of what is being said forms part of the flow of a conversation. Whether Alys was conducting the marriage or getting married to Gareth would be pretty clear from the general context, so whether the â was there or not would not really matter very much.
With an isolated sentence or fragment of the type that is used in Duolingo there is no context, so the little things which missed out or included can make a real difference to the potential meaning.
I was convinced that around the same time Pobol y Cwm was on BBC 2, they also used to show Ivor the Engine in Welsh, then repeat later in the afternoon in English. However, despite various searching around I have found no mention of this - so I'm beginning to think I may have just dreamt it. Does anyone else have any recollection of this? This would have been after it moved to BBC 2 and not when it was originally shown on ITV.
What dialect of Welsh is used for Pobol y Cwn? I believe it is set in the South in the Gwendraeth Valley and so I imagine it would be South Wallian? Wikipedia says little attempt is made to match accents to the locality.
Also according to Wikipedia, Pobol y Cwm is the BBC's longest-running soap opera.