Is 'dach chi'n' really proper? I don't think it's been introduced previous to this.
Dach chi is what I would say in the north. Both dach chi and dych chi come from the more formal forms Rydach chi and Rydych chi, and both are correct.
That's really cool, just as we have middle English as used in old poems and plays, there is middle Welsh. Have you ever seen a Welsh period drama production where the characters speak in middle welsh?
No, I wouldn't say it is. It's properly spelt "Ydych chi'n?" But if I have a coversation in Welsh that's how I'd say it.
Is there any difference in meaning between using dach and dych here?
No; it's like "mom" and "mum" in English, or "pyjama" and "pajama" -- just a dialect/regional difference.
They really need to get this course in order. I've been presented with a number of terms that I haven't seen before, without explanation or a definition.
I'm guessing they do that to get learners to think outside the box.
I'm stuck none of the answers I'm pressing are accepted !
Where on earth did "casell", or castle in welsh come from "Do you like Neath?"
Because "Neath" is "Castell Nedd" in Welsh.