"Jestem członkiem tej grupy."

Translation: I am a member of this group.

[Donoav]

Interestingly, 'member' can mean either 'a person who belongs to a group' or 'a penis', as well as it is in Polish (członek) and East Slavic languages (член).

[Jellei]

It somehow can also mean "a limb", although that meaning is rather dated and I'd only expect it in plural ("członki", which is different from the plural for "member of a group", which would be "członkowie").

[Kulink]

The implicit "ja" is in nominative/mianownik, and "członkiem" is in instrumental/narzędnik, what case is "tej grupy" in?

[mihxal]

Genitive

[Gatu77]

She has intonation as if she is asking.

[Jellei]

Yeah, the audio has a wrong intonation probably more often than a correct one :/

[Hel667660]

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.

[Jellei]

Well, you just can't do it with countable nouns.

[AnnaKupec]

Couldn't it also be "I'm (a) part of this group?"

[JerryMcCarthy99]

It's not really a reversible translation.

Although a "member" could be a "part", a "part" is not always a "member". A replacement headlamp for a car, for example, is a "part", but is never a "member".