"I was there for a year."

Translation: Dw i 'na ers blwyddyn.

[crush]

This doesn't need a past tense verb? I would assume this meant "I have been here for a year" (implying i'm still here).

[EllisVaughan]

That is correct, for me "I was there for a year" would be "Roeddwn i yna am flwyddyn" (or other ways of phrasing it.

[JamesTWils]

Why does fan hyn have to come before the verb, but yna comes after?

[MatjSuchne]

an year