So far everything that has been taught about "is" as a positive statement has been using "mae" in the third person, e.g. - as an example in this module - "Mae Cymru yn Ewrop". We have been told that "ydy" is used when asking a question in the third person, e.g. "Ydy hi'n gweithio?". So how come ydy suddenly appears in this expression to mean "is"? Does that mean I could have been saying all along "Megan ydy x", rather than "Mae Megan x" to mean "Megan is something or other"? Why isn't it "Mae Ewrop yn Cyfandir"?
Thanks for the question.
The difference in the construction of Welsh sentences is explained in the notes.
As you say the usual pattern is
Mae Megan yn hapus = Megan is happy
Ydy Megan yn hapus? = Is Megan happy?
However in some circumstances this word order is altered. This is usually to express emphasis or equivalence.
eg for names:-
Sioned ydy hi = She is Sioned Gareth dw i = I am Gareth
We can't use 'Mae hi'n Sioned' in this example because that would mean 'she is a Sioned'
ditto 'dw i'n Gareth' since that would translate as 'I am a Gareth'
In the example above 'Mae Ewrop yn gyfandir' is a correct sentence but the contributor of this sentence was using his own dialect rather than the standard course and preferred the emphatic, which probably needs an exclamation mark.
Cyfandir yw Ewrop! = Europe is a continent!
Many thanks for this reply. I actually posed that question a few weeks ago and since then, having completed further modules, this aspect makes more sense (well, a bit more, anyway!)