"Ffermwr dw i."
Translation:I'm a farmer.
The verb 'to be' ('bod', of which 'dw' is the 1st person singular, present tense, form) does not really have an object. It's called a copula, I think, where 'ffermwr' and 'i' are equated to each other, both being the same person. The order of the sentence denotes a sort of emphasis, whereby the speaker tells us that he is a farmer (as opposed to something else, e.g. a teacher). That is why 'ffermwr' comes first.