The imperfect is much more frequently used in Italian than in English. It expresses the English "used to" and is used to describe actions or conditions that lasted an indefinite time in the past. It's also used to express an habitual action in the past and to describe time, age, and weather in the past.
There are several little statement in this statement. Let' s discuss about it step by step.
1) The imperfect is much mor frequently used in Italian than in English.
That' s quite easy to say, but difficult to proove statistically and from a pure logical point of view it doesn' t seem very plausible. We presume that he want to say that the Italian imperfetto is used more often than the English simple past. Is that plausible from a logic point of view? The functions of the English simple past is realised in Italian by TWO tenses, the imperfetto and the passato remoto (or with the passato prossimo in modern Italian). Therefore it is much more plausible that the imperfetto is less frequent than the simple past in English. Perhaps things became more understandable with an example.
a) To describe a singular action in the past, we use the simple past in English, but the passato remoto / passato prossimo in Italian.
I sold my car.
Ho venduto la mia macchina. / Vendei la
b) To describe an action which happens regularly in the past.
x) I used to read the newspaper every morning.
xx) Leggevo il giornale ogni mattina.
As you can see in these examples, the English simple past has two different functions, but these functions are distributed in Italian on two different tenses.
2) It expresses the English "used to" and is used to describe actions or conditions that lasted an indefinite time in the past.
That' s right. The Italian impferfetto describes actions which happens regularly in the past, in this case we use the perifrasis 'used to' in English and actions which are 'indefinit', in other words, actions where the beginning and the end is not known or irrelevant.
a) Action which happens regularly in the past
I used to bake my bread myself.
Di solito facevo il pane io stesso.
b) Indefinite action, where the beginning and the end is unknown or irrrelevant
The book was on the table.
Il libro era sulla tavola.
The error in the statement above is that the English simple past has a third functions, actions which happens only once in the past (He left the room) are described with the simple past as well, therefore it is not possible to equate the Italian imperfetto with the English simple past.
It's also used to express an habitual action in the past and to describe time, age, and weather in the past.
This statement is somehow weired. The 'habitual action' has already been mentioned, these are actions which we describe with the periphrases 'used to' in English. A periphrasis is a verbal construction which includes the meaning of an adverb or an adverbial adjunct.
I used to read the newspapers every morning.
Normally I read the newspapes every morning.
There are no similiar periphrases in Italian. In Italian this kind of construction has to be translated with an adverb. (There is a similar construction in Spanish though: Solía leer los periódicos por la mañana.) The problem with this statement is that it suggests that the simple past can be translatet always with the Italian imperfetto. That' s not the case, because singular actions in the past are described with the simple past as well, but never with the imperfetto. Singular actions are described in Italian with the passato remoto (in the classical literature) or with the passato prossimo, in modern Italian.
In Italian the preterite is usually called Passato Remoto (simple past or past absolute, literally "remote past"). Like in Spanish and French, it is a past tense that indicates an action taken once in the past that was completed at some point in the past (mangiai, "I ate"). This is as opposed to the imperfetto tense, which refers to any repeated, continuous, or habitual past action (mangiavo, "I ate" or "I was eating" or "I used to eat"). In the spoken language of most of Italy (a notable exception is in Sicily), the passato remoto is not normally used, the compound passato prossimo tense taking its place (ho mangiato, "I have eaten" but also "I ate"). An exception to this is when there is emphasis on the remoteness of an action (i.e. Marco Polo andò in Cina nel 1264 (Marco Polo went to China in 1264) would be more proper than Marco Polo è andato in Cina nel 1264).
The problem with this statement is similar to the problem before, but inverse. In the first statement they attribute the first two function to the simple past (repeated actions in the past / description of a state in the past), but forgot the third one (description of singular action in the past). It is true so that the simple past corresponds to the passato remoto (passato prossimo), but only (!) if the simple past describes an action which happens only once in the past. This statement, as well as the statement before, is only half of the truth, and half of the truth is very similar to wrong.
The rest is more ore less right. The passato remoto is not used at all in nowadays Italian in the north of Italy (Bologno, Florence, Milano etc.). In the the south of Italy (Naples, Rome, Bari etc.) the passato remoto is used.
The passato prossimo, which is usually called the “present perfect” or “perfect” in English grammar, is formed by the auxiliary verb essere or avere followed by the participio passato (past participle): e.g. sono andata (I have gone), ho fatto (I have done). The passato prossimo is the main tense used in Italian to convey an action which has been completed in the past, and is used to translate both the English present perfect and the simple past: e.g.: ho giá visto quel film (I have already seen that film), ho visto quel film sabato scorso (I saw that film last Saturday).
Once again a similar problem as those we have seen before. It is not really a good idea to say that the passato prossimo corresponds to the present perfect in English. That would be true it the use of the passato prossimo if the passato prossimo were used in nowadays Italian the same way as it was used 200 years ago, but that' s not the case. The passato prossimo have assumed in nowadays Italian functions of the passato remoto, can be used so to describe a singular action in the past, in other words, it can be used when you use the simple past in English. So this sentence is once again only the half of the truth and the half of the truth is completely wrong.
'The passato prossimo is the main tense used in Italian to convey an action which has been completed in the past, and is used to translate both the English present perfect and the simple past.'
That suggests that you can always translate the passato prossimo with a present perfect or a simple past and that a present perfect or a simple past can be always translated with a passato prossimo. Thats completely wrong and it doesn't explain really when a the passato prossimo must be translated with a simple past and when it must be translated with a present perfect.
The clause 'has been completed in the past' is wrong as well, because the passato prossimo as it is used in literature is a time which describes an action which happened in the present of the speaker, the consequences of this action are still relevant for him.
The statement doesn' t contain the crucial information. We have two distinguish between three different situations.
If the passato prossimo appears in classical literature or in the south of Italy, the consequences of the action described by the verb in passato prossimo are already perceptible in the the present of the speaker,
which is not necessarly 'our' present.
I have worked the whole day, I am tired now.
Ho lavorato tutta la giornata, sono stanco.
If it appears in a sentence in nowadays Italian
it can be translated with the simple past in two different situation.
In a chain oft actions
He entered the room, said hello and sat down.
È entrato nella stanza, ha salutato e si è seduto.
In a situation where the consequences of an action are still perceptible in the present.
I have worked the whole day, I am tired now.
Ho lavorato tutta la giornata, sono stanco adesso.
Even if it is true that at least in nowadays Italian the passato prossimo is translated with a simple past or present perfect the rule is not very usefull. Of course we know which time to use when we translate to English, but in general we translate from English to Italian, at least in a real life situation, and than it is important to know whether to translate with a simple past or with a present perfect.
I) valid rule, but not really usefull
passato prossimo => simple past, present perfect
II) invalid rule (but much more interesting)
simple past, present perfect => passato prossimo
The I) rule works, because if we translate to English we know which time to use, but that' s not our problem. The II) is the interesting part, how to translate from English to Italian, but that rule is wrong.
simple past translated with passato prossimo (description of an action that had happened in the past)
I wrote him a letter yesterday. => Gli ho scritto una carta.
simple past translated with an imperfetto (description of a state in the past)
He was sad. => Era triste.
It is possible to say that a present perfect can be translated always with a passato prossimo. But it is not possible to say that a simple past can always be translated with a passato prossimo.