Brian can't believe that Wendy's actually contacted an estate agent behind his back to discuss putting their house on the market. He says:
Brian - Wendy - ateb fi! Wyt ti wedi ffonio estate agent go iawn?

You're probably familiar with the word 'iawn' in the phrase 'Diolch yn fawr iawn' - 'thank you very much', where iawn means 'very'. But you may not have come across the phrase go iawn yet. Go iawn means 'real' or 'really and truly'. So when Brian says, 'Wyt ti wedi ffonio estate agent go iawn?' he means, 'Have you really and truly phoned an estate agent?' The little word go can't be used on its own, but you may have come across it in another common phrase - 'go lew', where it can mean 'not so bad' or 'not so good', depending on your tone of voice. So if someone asks you how you are, and you say, 'go lew' in a bright and cheerful voice, you're quite well, but if you reply 'go lew' in a more miserable tone, you're not feeling too good.

Wendy tells Arwyn that when he returns to Wales again, Brian and she will have moved house. Arwyn then asks her, 'I ble ydych chi'n mynd?' - 'Where are you going to?' In Welsh, you must place the preposition 'i', which, as you know, means 'to', right at the beginning of the question, not at the end. So you say 'To where are are you going?' 'I ble ydych chi'n mynd?' not 'Ble ydych chi'n mynd i? which is a direct translation from English.

When Arwyn asks Brian and Jac if they'll excuse him, because he has to go somewhere else, he says, 'Os wnewch chi fy esgusodi fi...' 'Wnewch chi', which can be translated here as 'will you?' is not to be confused with' fyddwch chi?', which also means 'will you?'. But there's a difference in function between the two. 'Fyddwch chi?' is an enquiry about your future plans, whereas 'wnewch chi?' indicates a request.

Listen to the following and decide which of them is an enquiry and which is a request.
Here they are:

Will you open the window?
Yes, it's a request and you'd translate it 'Wnewch chi agor y ffenestr.'

Will you be going to town today?
Yes, it's an enquiry and you'd translate it: Fyddwch chi'n mynd i'r dref?

Listen again
Will you shut the door!
Yes, it's a request and you'd translate it: Wnewch chi gau'r drws!

And finally: Will you be listening to Ysbyty Brynaber tomorrow night?
Of course you will.