"A good jumper"

Translation: Siwmper da

[Kate_Fishman]

Why did it mark me almost correct, and then show my exact answer as an alternate answer?

[MartinBann1]

Why the double d?

[EllisVaughan]

It should be "Siwmper dda" due to the fact that "Siwmper" is a feminine noun and therefore causes a soft mutation on following adjectives. Also note that "D" is pronounced differently to "Dd" i.e "D" is like an English "D" whereas "Dd" is pronounced like the "Th" in "This" and "That". (But not like the "Th" in "Thought" or "Through".