"I have drunk coffee."
Translation:Dw i wedi yfed coffi.
Please use the report button to report sentences that you believe are also acceptable. Although I'm not familiar with "Rwy" being used so maybe you mean "Rwyf".
Rwy'n... is quite widely used, especially in SW Wales and apparently also in academic writing and presenting. Rwyf is a little more formal in writing, perhaps, and also as Rwyf wedi... alongside Rwy'n....
Rwy comes from the literary yr wyf and is used in some areas, but dw i is by far the most common.
Although dw i is the version usually taught on Cymraeg i Oedolion courses, and it is the version that we teach on Duo as well, the forms dwi, rydw i and rwy are acceptable alternatives on Duo as well as they are widely used in the wild and are often found in the media.
We do not use slang forms or literary forms.
Dw i is still more common. Rwy and Rw i are found in pockets around Wales. I once had a map showing the different areas where the different forms are used. Interesting stuff.
Also correct, it's not the Cymraeg taught in the Cyrsiau i Oedolion upon which the Duolingo course is set.