"Yes, they had miserable weather!"
Translation:Do, cawson nhw dywydd diflas!
'chaethon' : negative statement ( aspirate mutation). 'chaethon nhw ddim...'.
Caethon : positive statement. 'caethon' is the root form: no mutation. 'mi gaethon' (soft mutation after 'mi') is also for positive statements. 'gaethon' is also apparently often used even for positive statements.
'Gaethon' - soft mutation, without 'mi' - is also for questions.
As I understand it, 'caethon' is one valid option.
'Cawson' is also ok.
'Mi gaethon' is also ok.
'Gaethon' is also ok, but duolingo is phasing this alternative out of their teaching to bring their course in line with another, national - I think - course which doesn't introduce learners to that alternative. Presumably to try to reduce confusion and get us used to the idea that mutations mean questions / negations!
There is no new word for miserable - all through this course it is diflas, although the initial d- may take a mutation for various reasons.
There is no * dawson.
The course notes are there to help you. To find the course notes generally, go to https://forum.duolingo.com/topic/924/hot and see 'Course tips and notes'. The 'duome' link there is useful for browsing all the notes in one place. We recommend reading the notes for each new section as you start it.