"Who's going to start?"
"Start" is another way of saying first. The idea that they will begin and then others will follow after them.
"Who's up first?"
You are asking who wants to be the first one to sing or participate in any activity. This is more polite than saying "I"m first!" You are politely offering to allow someone else to go first.
"Who's going to start?"
誰から始める？
"Start"は、firstと同じで、はじめるという意味です。その人が始めて、他の人が続くという感じです。
"Who's up first?"
誰がはじめにいく？
誰がはじめに歌いたいか、何かに参加したいかを聞く表現です。 "I"m first!"「わたしが先！」と主張するより丁寧な表現です。丁寧に、誰かはじめに行きたいか聞く表現です。
*Who's first?- This would be short and direct way of asking something that everyone knows.
*Who would like to show off his/her talent first?- Talent is a skill or gift to exceptionally do something.
Example Sentences:
James is talented in swimming.
I think she was born a baker, she's talented.
*Who's first?
誰が先？
これは、みんなが知っていることに対して、誰が先にそれをするのか直接的に聞く方法です。
*Who would like to show off his/her talent first?
誰が初めに自分の腕を見せつけたい？
Talent とは、何かに対する能力、スキルのこと。
例：
James is talented in swimming.
ジェームスは、泳ぎの才能がある。
I think she was born a baker, she's talented.
彼女は、パン屋になるべくして産まれたと思う。才能があるわ。
"What wants to sing first?" This asks the friends to tell you who wants to sing before the others.
"Who wants to go first?" This is another way of asking who wants to sing first.
例文
"What wants to sing first?"
誰が最初に歌いたい？
他の人の前に誰が歌いたいかを友達に尋ねています。
例文
"Who wants to go first?"
誰が最初に歌いたい？
誰が最初に歌いたいかを尋ねる別の表現です。
In context, just saying, 'Who's first?' Is enough.
To be up for something. This means to be prepared to do something, or to have a desire to do something.
'Who's up for a game of tennis?'
こういう場合は'Who's first?'（誰が最初？）だけで十分です。
To be up for something は何かのために準備していること、または何かしたいと思っていることです。
'Who's up for a game of tennis?'
テニスの試合したい人？
Who wants to go first is probably most common. Simple who question aimed at everyone. Would you like to go first is polite and would be more suited to asking a person rather than a group.
Who’s up first is very casual and only used with good friends
Who wants to go first（誰が先にいく？）はおそらく最も一般的な表現でしょう。whoを使った質問は、みんなに向けての質問になります。
Would you like to go first?（先にいきたいですか？）は、丁寧で、グループ全体に尋ねるよりも1人に向けて尋ねるときのフレーズです。
Who’s up first?（誰が先にいく？）は、とてもカジュアルで、仲のいい友達だけに使います。
Who is up first' means you are asking who is going up on the stage first. This could be used along with a gesture such as pointing at the stage or nodding your head towards it to give the statement context.
Who is up first?' とは、誰がステージに先に上がるか聞いているという意味です。ステージを指したり、ステージの方に頭を向けたりジェスチャーをつけて言うといいでしょう。
As we can see there are many verbs that we can use within the same sentence construction to still keep the same meaning. "to go," and, "to start," would be the most general as we are not giving context of what the action is within the sentence, whereas, "to sing," gives us the verb of action within the phrase.
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