'Yet' and 'already' are often used with Present Perfect.
Which of them is preferred in sentences like this:
Is your father here yet (or already?)? Yes, he has just come.
'Yet' is used to say that it is expected that something has happened and used in negative sentences and in questions, so in the sentence above it seems that it is used correctly.
But is it possible to use already in this question? Would already sound naturally here?
Best Answer
The difference is illustrated by imagining a blind passenger asking the car driver...
...where the different implications are...
To put it another way, in such contexts, yet = after so much time, already = after so little time. That's to say, use yet if you were expecting/hoping for earlier, or already if you were expecting later (but not yet).
Note that both words can be used in contexts where either or both of expectation/likelihood and hope/desire are involved. In practice it makes no difference if an impatient child on a long car journey asks "Are we there yet?" or "Aren't we there yet?". But in other contexts, framing such questions in the negative often comes across as rude/impatient/accusatory, rather than a neutral request for information.