"May I ask a question?"
Translation:Ga i ofyn cwestiwn?
Gofyn and Ofyn both mean 'ask' in English.
The reason that they look different is because of an important feature of the Celtic languages.
This is the softening of initial consonants in words under certain circumstances.
In Welsh this is called 'mutation' and this unit introduces the most common one in Welsh.
There is more detailed explanation in the unit notes:-
Linguistically, nothing. Lexically, gofyn has changed to ofyn because "Ga i" creates a soft mutation so that the 'g' drops off.
I used Gaf i, instead of Ga I, it said this was a typo. However as far as I am concerned both are acceptable.