In italiano, quando si usa il presente e quando il gerundio?

Question

In English it is very common to use the present-conjugation of 'to be' plus the ing-gerund form of the verb to describe an action in progress.

Ex: "I am talking to Tom".

Would both of the following be correct?

1) Parlo con/a Tom 2) Sto parlando con/a Tom

In contrast, if I wanted to say: "I talk to Tom", meaning that I am not currently talking to him, but on occasion we talk with each other, how would you differentiate that from Parlo con Tom?

This is just an example using one verb, but I would like to know when either case is more appropriate.

Answer 1

I reply as Italian mother tongue, I'm not an Italian teacher, hence my answer is practical, not technical.

I think stare + gerundio is more or less like the -ing form in English: the present simple is used for habits, while stare + gerundio is used for actions happening in this moment, for example:

Di solito leggo libri di fantascienza (habit), ma in questi giorni sto leggendo un libro giallo (now) --> correct

It is NOT correct to say:

Di solito sto leggendo libri di fantascienza (habit), ma in questi giorni leggo un libro giallo (now) --> not correct

Differently from English, we don't use stare + gerundio for the near future, for example it is NOT correct to say:

Domani sto andando al mercato --> not correct

while it is correct:

Domani andrò al mercato --> correct

Domani vado al mercato --> not completely grammatically correct but largely used in informal Italian