Italian has a number of verbal constructions with infinitive or gerund, where the main verb has lost its original meaning and has become a marker of the aspect of the verb in the infinitive or gerund.

Stare + gerund

Usually only present and imperfect (less common with future and conditional). It is known as the “progressive” periphrasis because it emphasizes the ongoing nature of an action in a particular moment of time. However, it is much more limited in its uses than the English progressive tenses. In many situations where English uses a progressive present or imperfect, it is just as common in Italian to use a simple tense. Thus, although this Italian construction is becoming more widely used in Italy, it should not be overused by the learner, since it is only used to make the action more vivid, actual, or relevant to the situation at hand.

Compare:

Che fa Elena? Parla al telefono.

What is Elena doing? She is talking on the telephone.

Non interrompermi: non vedi che sto parlando al telefono?

Don't interrupt me; can't you see I am talking on the phone?

These uses of the English progressive can not be translated by stare + gerund:

(i) verbs expressing a state of affairs (sta essendo is ungrammatical):

Rosaria abita/vive a Napoli.

Rosaria is living in Naples.