
I've found that pubs and restaurants even in ardaloedd Cymraeg often don't provide much of an opportunity to speak Welsh, because of the tendency to employ temp staff from far afield, even if the owner is local. So I was pleased to find that I'd guessed correctly this time with the Plas Coch in the town centre (which is easy to spot: the name gives it away

Every single member of staff I saw was a Welsh speaker, and although we were the first people into the pub, within half an hour the place was full, and all the other diners were Welsh speaking too (including a good number of families with young children). Admittedly the food was only passable, but that's often the case with Sunday roasts. They had some good guest beers including Cwrw Llŷn, and most importantly for me, plenty of opportunity to use my Welsh. I only noticed the very faded "Croeso i Ddysgwyr" sign on the way out, but they certainly seemed welcoming enough.
In summary, worth a visit!