Where 'già', 'mai', 'sempre' and 'ancora' go in compound tenses
In Italian compound tenses such as the passato prossimo, a handful of short, very common adverbs like to squeeze into the gap between the auxiliary (avere or essere) and the past participle. You say ho già mangiato, non sono mai stato, ho sempre voluto. The adverb sits in the middle, like a filling in a sandwich.
English speakers often get this half right. I have already eaten has the same order, so già feels easy. But English moves other words to the end of the sentence: I haven't seen it yet, I've almost finished it now. Learners then copy that and say non l'ho visto ancora or put the adverb before the auxiliary. This article shows which words normally take the middle slot and where they are more flexible.
The pattern is always the same: auxiliary + adverb + past participle. Everything else keeps its usual place. Non and object pronouns such as lo, ci or ne go in front of the auxiliary, and the adverb waits after it.
Notice how the two languages differ here. English puts yet at the very end, while Italian keeps già and ancora right after hai and ho. A useful rule of thumb: find the auxiliary, and put the little adverb straight after it. The same order also works with other compound tenses, for example avevo già mangiato (I had already eaten).
The rule is a strong preference, not an absolute law. Other positions are sometimes heard for emphasis. The middle slot is always correct, though, and it is the most natural choice in everyday speech.
Già means already in statements and yet in questions. It almost always sits in the middle.
Mai means never with non, and ever in questions. The non goes before the auxiliary, and mai goes after it.
Sempre (always) follows the same order as in English.
Ancora in the sense of still becomes not yet with non in compound tenses. This is where English speakers slip most often.
Quasi (almost) also takes the middle slot. English often uses a simple past here, but Italian uses the passato prossimo with quasi in the middle.
Two more short words you will meet later work the same way: appena (ho appena mangiato, I've just eaten) and più with non (non l'ho più visto, I never saw him again).
The typical mistake is to push the adverb to the end, English style. Non ho finito ancora is understood, but it sounds foreign. Say non ho ancora finito. Also avoid putting the adverb before the auxiliary: non mai sono stato is simply wrong.
Not every adverb is this fussy. Spesso (often) is free: ho spesso mangiato qui and ho mangiato spesso qui are both fine, and the second is actually more common. Ancora in the sense of again usually goes after the participle, as in ho sbagliato ancora (I got it wrong again). Longer adverbs, such as bene or ieri, normally come after the participle: ho dormito bene.
Finally, remember that in simple tenses there is no gap to fill, so the adverb just follows the verb: mangio sempre qui, non vado mai al cinema.
In compound tenses, put già, mai, sempre, ancora (still, not yet) and quasi straight after the auxiliary and before the past participle: ho già mangiato, non è ancora arrivato. Non and pronouns go in front of the auxiliary. Resist the English habit of moving yet to the end of the sentence.