1. The phrase dyflwydd occurs this week. Dyflwydd is a shortened version of dwy flwydd which means two years old.

The word for 'year', when it's used without any preceding numbers, is blwyddyn

We'd say: Blwyddyn yn ôl - a year ago

However when talking about someone's age we have to say blwydd.

Mae hi'n dair blwydd oed
She's three years old.
Mae o'n bedair blwydd oed.
He's four years old.

So when you hear Wendy telling Jenny that Vicky is now 'dyflwydd a hanner' she's saying that the child is two and a half - or literally: two years and a half.

2. If you want to say 'the two of you, or you two', you could say chi eich dau

Pob lwc i chi'ch dau - Good luck to the two of you.

But when Jenny asks Wendy about Vicky and Frank, she says:

Sut maen nhw ill dau? - How are the two of them or how are they both?

ill can also be used with other numbers as well. For example:

Dewch ill tri - Come on, you three

ill corresponds to eich in these examples but it can also replace ein when referring to 'us' and it can replace eu when referring to 'them'. Let's look at some examples:

Dyn ni'n dau yn mynd i briodi
The two of us are going to get married - but you could just as easily say:
Dyn ni ill dau yn mynd i briodi

Maen nhw eu tri yn edrych yn grêt

The three of them look great - or of course:

Maen nhw ill tri yn edrych yn grêt.

3. You've probably already come across sawl in the sense of 'how many?' - as in

Sawl diwrnod sydd mewn wythnos = How many days are there in a week?
Sawl mis sydd mewn blwyddyn. = How many months are there in a year?
But when sawl follows y or yr, it means 'whoever' or 'a specific person'

We hear Jenny telling Wendy that she won't be able to get her hands on the results of the DNA test before Brian does, as hospital tests can only be posted to the specific patient who asked for them:

Mae'n rhaid postio'r manylion i'r sawl sydd wedi gofyn amdanyn nhw.