"I sell trainers here."
Translation:Dw i'n gwerthu esgidiau rhedeg yma.
One fun trick with learning Welsh is I have to translate from Canadian English to British English before then crossing over to Welsh. "Trainers", as a term for shoes, is completely unknown in my idiolect.
In my idiolect, "running shoes" is the standard term. There may be areas of Canada where "sneakers" is standard, but I associate the term with American English.