I get the following:
a girl/daughter is merch
the girl/daughter is y ferch (feminine singular nouns mutate after y)
two girls/daughters is dwy ferch (dwy causes soft mutation)
a boy is bachgen
the boy is y bachgen
two boys is dau fachgen (dau causes soft mutation)
Please can someone explain why both dwy and dau mutate after y in the following sentences please:
‘The two boys are grown up’ is ‘Mae’r ddau fachgen wedi tyfu lan’ (10:52)
‘The two girls are grown up’ is ‘Mae’r ddwy ferch wedi tyfu lan’ (11:05)
I presume ‘dwy’ mutates to ‘ddwy’ because it matches the mutation in ‘y ferch’, but why does dau mutate to ddau?
