How do you say "You sleep so late" in Korean?
Not in a negative way but more of concern?

Question

Answer

"You sleep so late" = 너무 늦게 주무시네요 / 너무 늦게 자네. (You go to bed so [too] late)
"You sleep so late" = 너무 늦게까지 주무시네요 / 너무 늦게까지 자네. (You sleep in (in the morning) until so late)

* 늦게:  late (adv); at a late hour.
* 늦게까지:  until (it's) late.  Same as 늦도록.
* -네(요):  a sentence ending expressing a slight surprise or exclamation - smoother than normal endings like 자(요), 잔다, or 잡니다.