The implicit "ja" is in nominative/mianownik, and "członkiem" is in instrumental/narzędnik, what case is "tej grupy" in?
She has intonation as if she is asking.
Yeah, the audio has a wrong intonation probably more often than a correct one :/
Why can't the a be omitted from the answer? Is "I am member of this group" really wrong? No native English speaker, therefore the question.
Well, you just can't do it with countable nouns.
Couldn't it also be "I'm (a) part of this group?"