An alternative sentence pattern uses dim (not or none). A soft mutation of the verb is again present:
Ddaeth y myfyriwr ddim i'r dosbarth
Wnaethon ni ddim brynu'r tŷ
The word dim can appear with two meanings:
not - as in 'We are not going to the concert'
not any - as in 'There is not any milk in the kitchen
When dim represents 'not', then a soft mutation is applied:
Dydyn nhw ddim wedi cyrraedd eto
They have not arrived yet
Dydy'r bwyty ddim yn ddrud
The restaurant is not expensive
However, no treiglad is applied to dim if it has the meaning 'not any', for example:
Does dim llyfrau ar y silff
There are no books on the shelf
Doedd dim gwaith i'r glowyr
There was no work for the miners
Interrogative sentences may begin with the word 'a', which causes a soft mutation:
A fydd y teulu'n aros yn y gwesty?
Will the family stay in the hotel?
A welsoch chi'r machlud hyfryd?
Did you see the beautiful sunset?
The initial 'a' can be omitted, but a soft mutation is still applied:
Fydd y teulu'n aros yn y gwesty?
Welsoch chi'r machlud hyfryd?