I'm from North Wales, and we always had breakfast, dinner (midday) then tea (evening). If we had a light snack before bed, that was supper. Now I live in London so I have breakfast, lunch (midday) and dinner (evening), unless I'm visiting posh friends, then the evening meal is supper. Simples! ;)
It sounds reasonably natural. A lot depends on the context in which things are being said, though, and of course an automated system such as this will not get things 100% anyway. The best way to learn general intonation and accent is by listening to natural speech, but that can be hard when you are just starting to learn and cannot yet recognise very many words.
Look on the S4C sites for the programme Dal Ati, which is designed for learners. Also look on the Open University's 'Open Learn' site for the extracts from their old Croeso Welsh course - that has a number of listening tasks.