Is "Cei" the answer specifically to "Ga i..." and no other construction? Does it conjugate like "Nac ydw / wyt / ydi" etc? It seems just a transliteration of the word "Ok" to me. (Sorry, this question may be revealed to me soon in other parts of this lesson but I am very curious)
The negative particle na here causes an aspirate mutation of p- t- c- to ph- th- ch- and a soft mutation of other mutatable initial letters.
This is explained in the course notes. The meaning of having/getting in this context is included in the ga i?:
- Ga i fynd? - May I go? (no 'have' in the English)
- Ga i afai? - May I have an apple? (English needs a 'have' here to make sense, but Welsh does not need a separate word)
Welsh and English have very different patterns, so word-by-word translations often do not work very well.