There are two ways of saying should or ought to (which are treated as conceptually the same) in Welsh, using dylwn (south) and dylswn (north). It’s best to be aware of both, and let local usage dictate which one you use.
Do not use yn , and following verbnouns such as cerdded , to walk , will take soft mutation in the affirmative and interrogative, but do not mutate after dim . Dylswn is sometimes used with the affirmative particle mi which causes soft mutation.
Affirmative
English Welsh Alternative Examples I should, I ought to dylswn i mi ddylswn i dylswn i gerdded you should, you ought to dylset ti mi ddylset ti dylset ti gerdded he should, he ought to dylsai fo mi ddylsai fo dylsai fo gerdded she should, she ought to dylsai hi mi ddylsai hi dylsai hi gerdded Carys should, Carys ought to dylsai Carys mi ddylsai Carys dylsai Carys gerdded the girls should, the girls ought to dylsai’r merched mi ddylsai’r merched dylsai’r merched gerdded we should, we ought to dylsen ni mi ddylsen ni dylsen ni gerdded you should, you ought to dylsech chi mi ddylsech chi dylsech chi gerdded they should, they ought to dylsen nhw mi ddylsen nhw dylsen nhw gerdded
Interrogative
English Welsh Alternative Examples should I? ought I? ddylswn i? – ddylswn i gerdded? should you? ought you? ddylset ti? – ddylset ti gerdded? should he? ought he? ddylsai fo? – ddylsai fo gerdded? should she? ought she? ddylsai hi? – ddylsai hi gerdded? should Carys? ought Carys? ddylsai Carys? – ddylsai Carys gerdded? should the girls? ought the girls? ddylsai’r merched? – ddylsai’r merched gerdded? should we? ought we? ddylsen ni? – ddylsen ni gerdded? should you? ought you? ddylsech chi? – ddylsech chi gerdded? should they? ought they? ddylsen nhw? – ddylsen nhw gerdded?
Negative
English Welsh Alternative Examples I should not, I ought not ddylswn i ddim – ddylswn i ddim cerdded you should not, you ought not ddylset ti ddim – ddylset ti ddim cerdded he should not, he ought not ddylsai fo ddim – ddylsai fo ddim cerdded she should not, she ought not ddylsai hi ddim – ddylsai hi ddim cerdded Carys should not, Carys ought not ddylsai Carys ddim – ddylsai Carys ddim cerdded the girls should not, the girls ought not ddylsai’r merched ddim – ddylsai’r merched ddim cerdded we should not, we ought not ddylsen ni ddim – ddylsen ni ddim cerdded you should not, you ought not ddylsech chi ddim – ddylsech chi ddim cerdded they should not, they ought not ddylsen nhw ddim – ddylsen nhw ddim cerdded