'Sleep late' is a common phrase. It's about the time that you wake in the morning: it means continue sleeping until late (or later than usual) in the morning. For example, "I have to get up early to go to work during the week, but on Sundays I sleep late". This means that I wake up late - for example, at 9 or 10 am rather than 7 am. I have never heard anybody say 'sleep early'. You can say 'go to sleep early', meaning go to bed early in the evening to sleep, but I don't think that you can say 'sleep early' on its own.

Sleep late is when you sleep later than you normally would. IE: 'I am going to sleep in late tomorrow morning because I am so tired! Sleep early I would use when I am going to bed. Or talking in the past. IE: 'I want to go to sleep early as I am very tired.' Or 'I went to sleep early as I had an important meeting the next day.'

If you say, "I go to sleep late", it means you usually go to bed late in the night or early in the morning - midnight for example. If you say, "I go to sleep early", it means you usually go to bed early in the night - 6pm for example

You question is a bit vague, but I will do my best to answer. Usually we use late and early to describe when we go to sleep, although sometimes we can refer to when we wake up. Some examples of going to sleep: "I am going to sleep early tonight because I have to get up for work tomorrow morning." "I went to sleep late last night because I was at the bar with some friends." To refer to waking up late, we would use the verb phrase "sleep in", something like this: "My alarm clock didn't go off this morning, so I ended up sleeping in." Hope that helps!

Thank you, La. There are two different understandings about it, 但我更相信你的理解