in which or which...in?

兄はとても注意深い人なので、いつも実際に使うべき言葉と語るべき調子とを時間をかけて選ぶ。
My brother is such a careful person that he always spends a lot of time selecting the actual words which he should use and the tone in which he would speak.

これは並べ替えの問題ですが(the tone...speakまで）
the tone which he would speak in. とならないのはなぜですか？
前置詞＋関係代名詞の時、前置詞は後ろに残しても、関係代名詞とくっつけても良いはず。
ここの問いで、in whichとしかならない理由を教えてください。

No.2 回答者： Syntactic_Structures 回答日時： 2022/12/08 11:25

分離しても構いません。

実例を挙げます。
The tone he was speaking in really concerned me and I could tell that something was really off.

He didn't like the TONE she was speaking in.

The tone he spoke in was harsh, and hissing, ...

The tone she spoke in made people curious.

No.1 回答者： isoworld 回答日時： 2022/12/07 21:31

なりません。

he tone which he would speak in とすると、in があまりにも遠い位置に来て、分かりにくくなるからです。