I saw your post and thought someone else would have answered by now. As they haven’t, I’ll have a go at confirming or improving your suggestions. Please bear in mind that I’m not a first language speaker. Also I speak North Wales Welsh.
Vincent dw i.
This is the correct way to introduce yourself.
Dw i’n byw yn Rossum, pentref bag yn Yr Iseldiroedd.
Did you mean “pentref bach”? Otherwise that correct.
Mae’n gorwedd rhwng dwy afon fawr, Waal a Maas.
I hope that a first language speaker can comment here, but this doesn’t feel quite right to me. I may be completely wrong but I’ve only come across “gorwedd” in terms of people lying down. I would suggest you try:
“Mae Rossum wedi’i leoli rhwng dwy afon fawr, Waal a Maas.”
(Rossum is situated between two big rivers, Waal and Maas.)
Dwi’n briod â Gerdie a dw i wedi ymddeol.
I think this is fine.
Hoffwn ddysgu Cymraeg pan fyddaf ar wyliau.
This is OK, but “fyddaf” is rather formal, so I would say, “pan fydda i ar wyliau.”
Mae fy hobi yn adrodd straeon.
If you mean your hobby is telling stories", i.e. as an oral story teller, then it would be “deud straeon”. However, it sounds a bit stiff to me so I’d say something like, “Dw i’n mwynhau deud straeon,” or if you are a writer, then it would be, “Dw i’n mwynhau 'sgwennu straeon.” Or you could use “licio” instead of “mwynhau”.
I’m going to pause at this point and carry on in another reply.
Margaret’s done an great job so far - and has reminded me that I was going to reply to this but got so busy with work this week it slipped down the screen and I forgot!
I’ll just pick out a couple (because the rest, and those with Margaret’s notes, are fine)
Mae’n gorwedd rhwng dwy afon fawr, Waal a Maas.
You could use ‘lleoli’ as Margaret suggested, or I myself would go for “Mae’n sefyll rhwng ddwy afon fawr, Waal a Maas”
Cyfarfûm â Daniel Morden, storïwr enwog o Gymru.
Although this is technically correct, hardly anyone would use this form of verb in everyday speech, so I would say either “Nes i gwrdd â Daniel Morden” or “Cwrddais i â Daniel Morgan” or “Dwi wedi cwrdd â Daniel Morgan” (the first two translate as “I met”, the third as “I have met”)
Rydyn ni’n mynd ar wyliau gyda gwersyllwr.
I just want to check - do you go on holiday with a camper as in a person who camps (gwersyllwr) or a camper as in a camper-van (cerbyd gwersylla)?
Allet ti ddweud e bach yn arafall?
‘slower’ is ‘arafach’
But overall, well done - that’s all coming along really well!
Cyfarfûm â Daniel Morden, storïwr enwog o Gymru.
This is not wrong, but it’s not how anyone would say it because “cyfarfûm” is the literary form. “Dw i wedi cwrdd â Daniel Morden…” (I have met Daniel Morden) or “Wnes i gwrdd â…” (I met…) is better for speech.
Dw i’n hoffi’r awdur Cymraeg Niall Griffiths.
There are two words for Welsh in Welsh. Cymraeg is the language and Cymreig means pertaining to Wales. Gwartheg Duon Cymreig are Welsh Black Cattle. So as I see (after googling) that Niall Griffiths is Welsh but writes in English, he is an “awdur Cymreig”.
Rydyn ni’n mynd ar wyliau gyda gwersyllwr.
“Gwersyllwr” is a camper in the sense of a “person who camps”. I assume you mean a campervan, so I suggest: “Rydyn ni’n mynd ar wyliau gyda fan gwersylla.”
Allet ti ddweud e bach yn arafall?
Just need to change “arafall” to “arafach” and that’s OK.
Dw i’n trio siarad ychydig yn Gymraeg.
Dw i’n joio arwyddion dwyieithog.
Mae rhaid i fi ymarfer mwy, heddiw.
Gwnaeth y gân Yma o hyd argraff fawr arna i.
Yn union fel Dacw Nghariad gan Eve Goodman.
I think these are all fine.
