"May I have a cup of chocolate?"
Translation:Ga i baned o siocled?
Hot chocolate is already one of the accepted alternatives here. In Welsh it would be rarely added, in the English spoken in Wales it would be often left out.
Baned is a contraction of Gwpanaid (after mutation) which actually means 'a cup full' in the sense of a cup full of drink.
- Ga i ...? is followed by a soft mutation of its object - https://www.duolingo.com/skill/cy/Gai/tips-and-notes
cwpan is 'a cup', cwpan o siocled is a 'cup (made of) chocolate'. In Welsh we use 'a cupful of xxx', where 'a cupful' is usually paned (shortened from cwpanaid)
Ga i baned o siocled (poeth)? - May I have a cup of (hot) chocolate?
Sorry, I don't agree that hot is rarely used before chocolate in the English spoken in Wales. I have lived in Wales for almost 50 years and never heard the drink referred to as anything other than hot chocolate. A cup of chocolate just doesn't sound right when referring to a drink to me!