"Dych chi'n bwyta caws."

Translation: You eat cheese.

[MarkJones10]

I'm confused then, as the "dych" is usually associated with a question (which is what I was taught)

[MarkJones10]

You eat cheese? Where's the "Do you" in the English answer?!?

[xXBad_WolfXx]

It's not a question, so there's no need for "do you." The question "Do you eat cheese?" would be "Ydych chi'n bwyta caws?"

[Tatonka71]

So when you add the Y in front of a pronoun it essentially makes it a question?

[xXBad_WolfXx]

For that word specifically. For "ti", it'd be "wyt ti'n", i.e. "Wyt ti'n bwyta caws?" :)