This is what I saw. (In a fairly formal register)
Dyma’r hyn a welais fe ?
Dyma’r hyn a’i welais ?
…and a diolch enfawr to anyone willing to help!
Ian
I would say
Dyma beth welais i
But I’m not sure it’s correct, so it would be interesting to compare the answer from someone with a better knowledge than me!
I would say “Dyma be’ welais i” too which is the more commonly heard, but the relative clause way would, I think, be “Dyma’r hyn a welais (i)”. Literally, “This is the this which I saw”. No need for a ‘fe’ or an ’ a’i ’ in this construction because it’s not the ‘this’ that’s doing the seeing.
1 Like
Diolch unwaith eto, Siaron.
Dw i 64 oed a dw i wedi dysgu Cymraeg yn ddiweddar. Tua thair blynedd yn ôl dechreuais i sgwennu yn Gymraeg. Wedi sgwennu cerddi am sbel, dw i’n sgwennu rhyddiaith ar hyn o bryd. Dw i’n ennill cystadlaethau a chaiff fy nofel gyntaf ei chyhoeddi eleni. Ond dw i’n dal i wneud camgymeriadau. Dyma ran o’m hadborth.
“Heb os, dyma ymgais mwyaf uchelgeisiol, annisgwyl a chymhleth y gystadleuaeth hon…Does dim dwywaith, mae hon yn stori drawiadol. Fodd bynnag, nid yw’r gystrawen yn gywir bob amser.”
Mae fy Nghymraeg ysgrifenedig yn iawn ond o dro i dro byddaf yn gadael rhywbeth anghywir yn y testun. Nid yw sgwennu yn y Gymraeg yn hollol naturiol i mi eto, ond dw i’n trio mor mor galed i wella! Dw i’n ddiolchgar iawn i chi am eich atebion i’m cwestiynau. Mae’n anodd dod o hyd i atebion i gwestiynau manwl fel hyn, yn enwedig am gystrawennau ffurfiol.
Diolch unwaith eto felly
Ian, Machynlleth
Diolch am hynny, Gisella.
That’s what I would say in spoken Welsh. I’m trying hard to master written Welsh. I have different influences pulling in different directions as to how formally I should write. I have been encouraged to use the ‘yr hyn a’ construction, but I know most would say ‘beth’. I suppose I would like to have the option.
Thank you for taking the time to reply.
Cofion gorau. Ian
1 Like
Llongyfarchiadau Ian - ti’n neud arbennig o dda!
I’m replying (mostly) in English so that those less familiar with written Welsh can follow the thread if they need to.
You’re doing excellently - to tell the truth, you are pushing yourself far more than I ever have since I finished university coursework! I’m no expert on formal writing by any means, but I have plenty of textbooks and grammar books to refer to and the remnants of my uni learnings! 
All the best with your poetry and prose, and I hope there are many more competition wins coming your way!