In standard Italian, essere is the normal verb for location in sentences like this:
You may also hear stare in some contexts, but it usually adds a slightly different idea, such as staying somewhere or emphasizing being in a place for a period of time:
So for a simple question about someone’s location, essere is the most natural choice.
Già means already.
In sei già a casa?, it comes after the verb and before the place expression. That is a very natural position in Italian.
Compare:
Italian adverbs like già often go near the verb, but the exact position can vary a little depending on style and emphasis.
A casa is a fixed, very common expression meaning at home or sometimes home, depending on context.
Italian does not normally use an article here. So:
Using alla casa would usually mean to the house, referring to a specific house as a building, not the idea of home.
This is a very common question.
So:
Often a casa is the more natural choice when talking about being home in the general sense. In casa focuses more on being physically inside the house.
Ciao is informal. You use it with friends, family, classmates, coworkers you know well, and other informal situations.
It would not usually be appropriate in a formal situation. For example, with someone you don’t know well, you might prefer:
So Ciao, sei già a casa? sounds natural between people who are on informal tu terms.
Usually, no. Italian often keeps the same word order as a statement and shows a question through:
So:
Unlike English, Italian does not normally need a special do/are inversion rule beyond the normal verb form already being there.
To say it formally, you would normally change both the greeting and the verb form.
Informal:
Formal:
Here, Italian uses Lei for formal you, and the verb takes the third-person singular form:
Even if Lei is not stated, the verb è shows the formal form in context.
Già is pronounced roughly like jah.
The accent mark on à shows that the stress falls on that final syllable. In short words like this, the written accent is important.
A rough pronunciation guide for the whole sentence:
So the whole sentence is approximately:
CHOW, say jah ah KAH-zah?