"Megan dw i."
Translation:I am Megan.
I believe "i" is the same as English "I", that is the first person pronoun. Wiktionary tells me "dw" is a conjugation of "to be", and that the infinitive is "bod". Hence, if you directly translate this sentence it becomes "Megan am I".
Sorry, I am just starting out on this course myself so I am struggling along same as you...
Your question prompted me to do a little research, since there's nothing on this in the lesson notes.
Usually, Welsh is VSO (verb-subject-object), but when using bod ("to be") to equate two things ("X is Y"), it's common to put it as "Y bod X".
Yes, you're right. This structure is optional if Y is indefinite and mandatory if Y is defnite.
In addition and related to it, it's also the case that new or emphasised information usually comes first in Welsh. So you could say Dw i'n nyrs (I'm a nurse) or if the nurse part is new info or you want to emphasise it you can say Nyrs dw i (I'm a nurse). Another example would be Dw i'n byw yng Nghymru (I live in Wales) as opposed to Yng Nghymru dw i'n byw (I live in Wales).
This is why Welsh people when speaking English say stuff like "A nurse I am" and "In Wales I live". We're just mapping Welsh patterns on to English.
Yeah, so if you have an indefinite noun, you have a choice.
Mae hi'n nyrs (She's a nurse)
Nyrs yw hi (She's a nurse)
Whereas if the noun is definite, you can't use the verb-initial structure.
Y nyrs yw hi (She's the nurse / She's the nurse)
That's why you can't say Mae hi'n Megan unless you want it to mean "She's a Megan"!