Yes, I suppose so. (I can tell that you're asking about the door lying on [something].)

Oh, okay. That particular sentence was my somewhat clueless attempt at correcting "haws dweud na chathod i fynd oddi tanynt".

"on its [literally "her"] side"

Mae'n hwyr. Dylwn i fod yn y gwely.

Thank you. So I guess "mae'r ddôr yn gorwedd ar ei hochr". (I don't know how to say "yes" or "no" in any natlang other than English, French, Spanish and Russian.)

Sorry, I'll have to use a translator program for this one. Let's see what GT said: "It's late. I should be in bed."
I don't really have anything good to say to that, but at least I learned something.

Welsh is complicated in this respect since it famously does not have a single word for "yes" or for "no". Rather it repeats the main verb of the sentence. So the affirmative response to a question beginning with "Ydy?" is "Ydy" and the negative response is "Nag ydy".

Wyt ti'n deall y frawddeg 'ma?

Thank you. That sounds like what Portuguese does. It also sounds like something I've heard before.

GT again. "Do you understand the sentence here?" Assuming the verb is "wyt":
Nag wyt.

Also, mae'n hwyr, and you know what that means. Dylwn i fod yn y gwely.

Unfortunately, that reply means, "No, you don't." If what you mean is, "No, I don't", then you have to say "Nag ydw."

(This is all explained on the page I linked to.)

Oh, whoops. I was worried that might be the case.

I'm not sure what page you're referring to. I will have to look around for it.

In case anyone cares, I just came up with a really dumb short dialogue in Welsh. Here it is if anyone wants to proofread it.

For anyone who can't understand it, it's just a bunch of stuff about a fat cat sleeping on a door. It doesn't make much sense.

Nouns: Don't forget that cath and dôr are both feminine nouns. Adjectives which modify them must be mutated and conjugated prepositions which refer back to them must use feminine forms.

Verbs: Mae is a tricky verb to start with because it has more forms in the present than any other verb. Ydy is the interrogative form, the form used after nag in giving a negative answer, or after nad in a negative relative clause (i.e. "that is not"). Dydy is the negative form and mae is the corresponding declarative.

As I just explained on Unilang, Welsh negation is two-pronged, like French: in the absence of a negative pronoun (like neb "nobody"), the negative verb is reinforced with dim (mutated to ddim after the subject).

Here's a little dialogue. For practice, fill in the missing parts:

Llawygath: Lle mae'r gath?
Coesci: ___ hi'n cysgu ar y gwely.
Llawygath: ___'r gwely'n gynnes?
Coesci: Nag ___. Mae'r cynfasau [sheets] yn denau [thin].
Llawygath. Dim posibl! Chysgiff y gath ddim ar wely nad [that] ___ e ddim yn gynnes!

Thanks for the corrections. I was sure there'd be something I got wrong. Now I'll have to fix the web page that has this on it. (The public version of the page doesn't have the above dialogue on it at the moment, but it will soon.) Edit: I just updated the web page, and it now contains Linguoboy's version of the dialogue instead of the total silliness that it had on it before.

Oh, fooey. Thanks for pointing that out. I had no idea mae and ydy were forms of the same verb. I suppose I should have figured that out.

Sorry, but I wrote up the dialogue before you posted that on Unilang.

I filled in the verbs. I'd like to know if the words in brackets are translations, which I assume they are. Even so, I can't understand why the cat wouldn't sleep on the bed.
By the way, I like how you've used my Unilang username here, which so happens to be really meaningless Welsh (llaw y gath).