This can be quite tricky to define.
The 1st language for most of the peole who live here is Cymraig (Welsh), but you should have no difficulty in communicating as almost everyone can also speak English.
To help you on your way and as an introduction to the language here are some helpful hints:-
Bore Da - Good Morning
Diolch yn Fawr - Thank you very much
Diolch - Thanks
Nos Da - Goodnight
Bara - Bread
one two three - un dai tre
The pronounciation of letters differs in a few ways to English, u is sounded like an i, ff like an f, f like v, dd like th.
There is also the terrifying 'Mutations' of words where sometimes the spellings, and thus pronounciation, change depending on preceding letters. An example of this is 'Good Evening' which becomes Noswaith Dda (instead of noswaith da). In the context of Cymraig (Welsh) this makes perfect sense as noswaith da is quite difficult to say; in English one thief becomes 2 thieves as 2 thiefs is also quite tricky on the tongue.
A visit to the local book shop will contain a number of Local Authors - Phillip Pullman is probably one of the more well known - his book 'Northern Lights' became the film 'Golden Compass' with Nicole Kidman and Daniel Craig. However, if you search a little more and you'll find that Robert Graves (I Claudious) lived here for a while with his father AP Graves.
This is the land of Male Voice Choirs, Silver Bands and the Rugby Club.