"Dych chi wedi mynd i'r parc?"

Translation: Have you gone to the park?

[Robgprice]

"Have you gone " is bad English. We don't say that because if you are gone you are not here - so who am I talking to?

The correct English would be "have you BEEN to the park?"

[DaibhidhR]

There are different varieties of English. I (southern English) regard both as quite normal. It is funny how technology can change language as they have slightly different meanings to me: been would imply 'gone and come back'. Before the days of the mobile/cell the two would be indistinguishable. It would be a silly question to ask in the park, so if they had gone they would obviously have come back. But now I can ring someone on their mobile/cell and, not knowing where they are, say have you gone to the park with the possibility that they have gone but not yet come back.

So even in your dialect, I am guessing you would have to use gone if you were on your mobile/cell and the possibility existed that they were currently in the park?

[DaveyBpants]

That would translate as "wedi bod"