I do not think spalle in Italian sentence corresponds to back in English translation. “Talk back” is to reply defiantly or insolently when the person is present (usually). As always, feel free to correct.
Yes, “do not talk about me this way behind my back” , that is how I read and translated it and would definitely use it unless someone says otherwise. “Talk back” is something completely different.
I think the three linked versions ("Non parlare/parlate/parli di me… ") of this sentence about not “talking back”, which as @barcarolle already has pointed out means something else indeed, were just misinterpreted and thus mis-translated/mis-linked unintentionally, because the other languages do seem to convey the intended meaning of “Don’t talk back to me like that”, e.g. in