In American English, if you ask someone if they are up, it could mean that you are looking for something sexual, so it is best to ask if they are still awake, as in the first example.
In the second example, we talk about going to bed because even if that person is not asleep, they may no longer wish to talk to anyone. Or they could be preparing for bed and do not wish to be disturbed.
I hope this helps! :)
Are you still awake?
まだ起きてる?
Have you gone to bed yet?
もう寝た?
アメリカ英語では、誰かに they are upと聞くことは、性的な意味に捉えられることもあるので、はじめの例のように、they are still awakeと聞くのがベストです。
二つ目の例では、その人が寝ていなくても、誰とも話したくないのでgoing to bedと言うかもしれません。もしくは、[寝る](https://eikaiwa.dmm.com/uknow/questions/38675/)準備をしていて、[邪魔](https://eikaiwa.dmm.com/uknow/questions/38483/)されたくないと思っているかもしれません。
お役に立ちますように!(^^)
"awake" は、" wake up" で使う動詞の"wake([目を覚ます](https://eikaiwa.dmm.com/uknow/questions/74188/))"の形容詞で、意味は『[起きている](https://eikaiwa.dmm.com/uknow/questions/77776/)(状態)』です。
In American customs, the context depends on who you are sending it to. If you're sending it to a friend that you have a close relationship with, it would mean you're looking to talk to this person. But if you send it to someone you don't know really well, they might get another less innocent impression. But that differs from culture to culture.
Are you still awake? is a formal way of saying it with correct grammar.
You up? is informal and grammatically incorrect but used by many especially between friends.
アメリカの習慣では、これは誰に送るのか次第です。相手が親しい友人なら、その人と話をしたいという意味になります。相手がそれほど親しくない人なら、あまりいい印象を持たれないかもしれません。ただ、これは文化ごとに異なります。
Are you still awake?(まだ起きてますか?)は、正しい文法で、フォーマルな言い方です。
You up?(起きてる?)は、砕けた表現で文法的に正しくありませんが、特に友達同士でよく使われます。
When asking if a person is still awake or if a person has already gone to bed you will usually use a yes/ no question. You can ask questions like this: "Are you going to sleep yet?"
人がまだ起きているか、寝てしまったかどうかを尋ねるとき、たいていは一般疑問を使うでしょう。以下のように聞けます:
Are you going to sleep yet?
(まだ起きていますか?)
If you want to know if your friend is 'still awake', you may ask straightforwardly by texting if he/she is 'still awake' or 'still up'. Being 'still awake' means not being in dreamland as yet. One may be lying in bed but 'still awake' and not having fallen asleep as yet. A person who is lying in bed but 'still awake' can chat with you same as a person who is 'still up'. 'Still up' gives the impression that the person is 'still awake' and not lying in bed. He/she may be sitting at a table and can definitely chat with you.
So, you may text:
Are you still awake?
or
If you are still awake, please text "yes I am"
or
Are you still up?
友達がまだ寝ていないか知りたいなら、携帯メールを送ってストレートに「Are you still up [awake]?(まだ起きてる?)」と聞けるでしょう。
still awakeとは、まだ眠ってないという意味です。ベッドに入っていても起きている(still awake)ことはあります。ベッドに入っているけどまだ目が開いている人は起きている人と同じようにおしゃべりができます。「still up」には目が開いていて、ベッドにも入っていないというニュアンスがあります。テーブルに座っているかもしれませんし、間違いなく話はできます。
従って、下記のように携帯メールを送れます。
Are you still awake?
まだ起きてる?
If you are still awake, please text "yes I am"
まだ起きてるなら、「はい(Yes, I am)」とメールを送ってください。
Are you still up?
まだ起きてる?
You can ask if someone is sleeping, and if they are, they may not respond because they fell asleep. This is similar when asking if someone is still awake - if they don't reply, that may mean they fell asleep, or they can reply "yes" and you can continue with the conversation. These questions are usually asked when it is very late and past the usual time people have gone to sleep for the night. Generally, people prefer to go to bed around 10 P.M. or 11 P.M. in the United States, but bedtimes vary for different cultures and people.
「もう寝ましたか(Are you asleep yet?)」と聞けます。寝てる場合、返事をしないかもしれませんね。これは「まだ起きてますか(Are you still awake?)」に似てます。返事しなかったら、寝てるかもしれませんし、「Yes(はい)」と答えたら、話ができます。
こういう質問は普通、夜いつも寝る時間を過ぎた、すごく遅い時間に使われます。アメリカでは10P.M.か11P.M.頃に寝る人が多いですが、就寝時刻は文化や人にとって異なります。
The first example sentence is a positive question, whereas the second is a negative version. There is always another way to ask the same question - it just depends on the speaker's perspective and expectations.