That is the usual pronunciation of the letter 'u'.
If you look in the discussion on 'Pronunciation' you will see a link to some very good Youtube videos on Welsh pronunciation. We recommend that you go through these at regular intervals as you go through the course.
Welsh word order is not the same as English word order:
- dydd Sul - Sunday
- prynhawn - afternoon
- Prynhawn dydd Sul = Sunday afternoon
I find this very easy once you hear the pronunciation. I was worried that it would not follow the planetary pattern like the romance languages do, but it does in a way even more similar to English than those!
I thought the right pronunciation for 'dydd' was /dɨð/, though they seem to pronounce it here as /dið/. Can anybody explain me what is the right and standard pronunciation for 'y' in Welsh?
Accents (in English as well as in Welsh) do vary across Wales.
The pronunciation of u and clear y does change, gradually becoming 'darker' (more like /ɨ/) the further north-west you are. The computer-generated voice on Duo has a neutral accent that does not use the darker sound.
To hear the difference between someone from (probably) mid south Wales and someone from north-west Wales, watch the series of pronunciation videos that we recommend - look on the web for 'welsh plus pronunciation youtube'. You will notice that their English and Welsh accents are both different.
The dydd is optional. The database shows both prynhawn dydd Sul and prynhawn Sul as answers. Duo does sometimes trip over capital letters, so you could try a capital P- and see if that makes a difference - it shouldn't, but it may be what is causing your problem.