Level 3 Challenge 10 (South)

Please could someone explain why cyntaf mutates to gyntaf in the following sentences:

‘to come first’ ‘yn dod gyntaf’ (10:10)
‘what is first will be interesting’ ‘beth sy’n gyntaf fydd yn ddiddorol’ (11:01)
‘a show first’ ‘sioe gyntaf’ (13:15)

In the first two, the yn is causing the mutation because cyntaf is an adjective. In the third one, the mutation is being caused by the feminine noun sioe. :slight_smile:

Thanks! So if cyntaf is an adjective in the first sentence (to come first) would it be correct to say ‘yn dod yn gyntaf’ and the 2nd yn is dropped in speech?

“To come first” would be just dod yn gyntaf
e.g. I want to come first = Dwi’n moyn dod yn gyntaf

edit - I dare say people do, in fast colloquial speech, sometimes say dod gyntaf though. (the yn is implied by the mutation)
Also, if you wanted to say “coming first”, then that would be yn dod (yn) gyntaf
e.g. He is coming first = Mae e’n dod (yn) gyntaf