I just saw a video about saying how many children you have. The phrase for “I have one child” was “Mae un plentyn.” For two, it was “dau blentyn,” and for three it was “tri phlentyn.” I have never heard of the same word having more than one possible soft mutation. Can anyone explain this please?
1 Like
So plentyn is the unmutated word…
‘Two’ causes a soft mutation - making it blentyn
‘Three’ (and six) cause aspirate mutation to make it phlentyn.
So there are two different types of mutation involved here…
Rich 
1 Like
Thank you! I’m new to Welsh and did not know there was more than one kind of mutation. What fun!
1 Like
There are three in fact and here’s a BBC summary. I’ve been learning Welsh for centuries and still haven’t mastered them but nobody seems to mind. They are called “treigladau” which I suppose means you’ll be “glad you tried”. 
welshgrammar_mutations.pdf (46.1 KB)
4 Likes
Diolch, Huw!
Loads of videos on Youtube explaining the 3 types of mutations.
Oh blimey. I hate to throw a spanner in the works, but children is a very special case. Two children is dau o blant (two of children), three is tri o blant and so on. This pattern of using o and the plural usually only starts around a count of fourteen for other nouns, but for children it starts at two. No-one knows why.
Of course, you can say “dau blentyn” and everyone will understand, but just like if you said “dwy plentyn”, it would make sense but just sound very slightly strange.
1 Like
I don’t think there are many ‘chwech blentyn’ families these days.
1 Like