Sude ni and Mou

Both gave the english translation as "already" but what is the difference and on what occasion each of them be used?

thanks!

Sude ni, to me, is more like "already" as in "too late," with sort of a negative connotation.

Mou in this case is more general, as in "I already did my homework."

One difference is that "sude ni" is a phrase more often used in writing (formal), and "mou" is used in speech (colloquial, casual). Another difference is that "sude ni" is "already" in the past, clearly referring to something "done in the past." or "has already been done." "Mou" can be used in a wider range of meanings, almost in the same way as English "already."

For example,
- Kare wa mou uchi ni kaerimashita. (He already left for home.)
- Mou 5-ji desu. (It's already 5 o'clock.)
In the above, "sude ni" can be used as well, though it can sound a bit too formal if used in spoken language.

If you are at a party and friend says he is leaving, so you ask:
- Mou kaeru no? (Are you already leaving?)
Now this one is still in the present, but "already" is used in the sense of "it's still early but..." "Mou" has this meaning, but "sude ni" does not have this meaning.