"This" means 'here and now'. If we already spoke about it it becomes "that". The Polish grammar for " to" and "tamto" doesn't apply to English usage. Therefore when in Polish you say 'już rozmawiałyśmy o tym' itbwould be much more likely to translate "tym" to "that" since you are referring to the past. That being said, of course it could also refer to "this". For example, maybe there is a printed list of topics which is " here and now".
How would you translate the simple past tense, then? "We already talked about this."
Absolutely no difference.
Oh wait, not only it is not accepted, it also gives a message back. I don't see a reason why, but I'm gonna consult it.
Oh, of course. I must admit that I may get a little sloppy when doing the exercises with tiles in Android. I was surprised that the suggested translation used the English present perfect, though.
Not necessarily. "porozmawiałyśmy" sounds as if we were supposed to have a conversation about that and it indeed already happened. One conversation. "rozmawiałyśmy" just says that we talked about that. Perhaps once, perhaps more. Such words are hard to define precisely.
Almost. This construction is not wrong in English, but it's a little unnatural. "We have already been talking...," is better. Just like you can't split "we've," you shouldn't split "we have," either.