Blwyddyn Blues Part II


Croeso yn ôl! Welcome back.

Time to carry on with our collection of facts about the queen of Welsh language irregularities: Good old blwyddyn!

This is Blwyddyn Blues Part II and – beware! – it’s going to be worse than the first one. A LOT worse. Today will be about counting years. But before we start doing so in Welsh, we have to be specific about what exactly it is that we want to count: years in general OR years of life. Because yn Gymraeg, it does make a difference. The first requires blynedd and the latter requires blwydd.

Both require further investigation.

Counting years: Blynedd

We will start with counting years in general (as in “NOT years of life”).  The correct form you need for this is blynedd – unless you want to say “one year”, which is simply un flwyddyn. As we shall see.

Blynedd is feminine, just like blwyddyn. No surprise there. But this, of course, implies that when counting blynedd we need to use the feminine forms of the numbers. And, of course, we all remember (don’t we?) that some of these numbers cause mutations. What we duly expect is a soft mutation each after un and dwy – and a soft mutation after un and dwy it will be. Splendid.

BUT: In addition to that you will find that blynedd mutates (nasally) to mlynedd after many  other numbers – even though these numbers don’t cause a nasal mutation in any other word!!!!! See what I mean about the “queen of irregularities”?

So let’s do it. Let’s count years.

one year = un flwyddyn  (Soft mutation: b > f)

two years – dwy flynedd (Soft mutation: b > f)

three years – tair blynedd 

four years – pedair blynedd 

five years – pum mlynedd (Nasal Mutation: b > m)

Remember to drop the final -p in pump. Blends nicely this way, doesn’t it?

six years – chwe blynedd 

More droppings: No -ch at the end of chwech!

seven years – saith mlynedd (Nasal Mutation: b > m)

eight years – wyth mlynedd (Nasal Mutation: b > m)

nine years – naw mlynedd (Nasal Mutation: b > m)

ten years – deng mlynedd or deg mlynedd   (Nasal Mutation: b > m)

As the numbers get higher, things get more complicated. For one thing, the traditional and the modern system of counting come into it after deg. Plus you may either use a form of blynedd or the plural o flynyddoedd from here. As a result, there’s a lot of room for variation!

For example:

Here are three possible ways of saying “17 years”:

dwy flynedd ar bymtheg

un deg saith mlynedd

un deg saith o flynyddoedd

For today let’s concentrate on the traditional numbers in combination with blynedd:

11 years – un mlynedd ar ddeg  (Things can’t possibly get more irregular than that!!!!)

12 years – deuddeg mlynedd OR deuddeng mlynedd

13 years – tair blynedd ar ddeg

14 years – pedair blynedd ar ddeg

15 years – pymtheg mlynedd OR pymtheng mlynedd

16 years – un mlynedd ar bymtheg

17 years – dwy flynedd ar bymtheg

18 years – deunaw mlynedd 

19 years – pedair blynedd ar bymtheg

20  years – ugain mlynedd 

30 years – deng mlynedd ar hugain

40 years – deugain mlynedd 

50 years – hanner can mlynedd 

60 years – trigain mlynedd

70 years – de(n)g mlynedd a thrigain

80 years – pedwar ugain mlynedd

90 years – de(n)g mlynedd a phedwar ugain

100 years – can mlynedd 

Counting years of life: Blwydd

If we want to count years of life (as we do when we want to talk about age), we need to use a different form: blwydd. Once again, it’s a feminine noun. Once again, we need the feminine numbers. And once again, we need the same mutations as above for blynedd. Like this:

1 year old  – blwydd oed 

Mae fy mab yn flwydd oed heddiw. – My son is one year old today.

No need for the number un here! But you could also say:

Mae fy mab yn un oed heddiw. 

2 years old – dwy flwydd oed 

Mae fy mab yn ddwy flwydd oed. – My son is two years old.

3 years old – tair blwydd oed 

Mae fy mab yn dair blwydd oed. – My son is three years old.

4 years old – pedair blwydd oed

Mae fy mab yn bedair blwydd oed. – My son is four years old.

5 years old – pum mlwydd oed

Mae fy mab yn bum mlwydd oed. – My son is five years old.

6 years old – chwe blwydd oed 

7 years old – saith mlwydd oed

8 years old – wyth mlwydd oed

9 years old – naw mlwydd oed

10 years old – deng mlwydd oed OR deg mlwydd oed 

Mae fy mab yn dde(n)g mlwydd oed. – My son is ten years old.

And now the good news!!!!

If you don’t want to use blwydd, don’t. You don’t have to. You don’t really need it when talking about age:

Mae fy mab yn naw mlwydd oed.  =  Mae fy mab yn naw oed. 

That was rather a longish blogpost. Are you still there?

Diolch am eich amynedd! Thank you for your patience!

Hwyl fawr,



Cymraeg Geirfa: Blwyddyn Gramadeg: Cyfri

ymlaenwelsh View All →

I’m Susanne and I teach Welsh (oh, and English!) in Wolfenbüttel, Germany.

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