The following is an example of a bibliography of an imaginary translated book from English to Japanese.

[
  {
    "id": "morgan2023jiyu",
    "author": [
      { "family": "Morgan", "given": "Casey" },
      { "family": "Patrov", "given": "Alexei" }
    ],
    "citation-key": "morgan2023jiyu",
    "event-place": "東京",
    "issued": { "date-parts": [[2023]] },
    "language": "ja",
    "original-date": { "date-parts": [[2022]] },
    "original-publisher": "Global Academic Press",
    "original-publisher-place": "Chicago, IL",
    "original-title": "The Philosophy of Free Will",
    "publisher": "城南大学出版会",
    "publisher-place": "東京",
    "title": "自由意志の哲学",
    "translator": [{ "family": "鈴木", "given": "真紀" }],
    "type": "book"
  }
]

When I process the bibliography item with citeproc-js and a CSL-M style, citeproc-js produces citations as follows.

• Note Morgan Casey、Patrov Alexei『自由意志の哲学』訳：鈴木真紀（東京：城南大学出版会、2023）。〔The Philosophy of Free Will (Chicago, IL: Global Academic Press, 2022).〕
• Bibliography entry Morgan Casey、Patrov Alexei『自由意志の哲学』翻訳：鈴木真紀、東京：城南大学出版会、2023。〔The Philosophy of Free Will (Chicago, IL: Global Academic Press, 2022).〕

As far as I know, it's common to keep the name order in the original language for translated items in Japan, I propose adding follow-language-name-order option. Here is an example with citeproc.setFollowLanguageNameOrderOption(false).

• Note Casey Morgan、Alexei Patrov『自由意志の哲学』訳：鈴木真紀（東京：城南大学出版会、2023）。〔The Philosophy of Free Will (Chicago, IL: Global Academic Press, 2022).〕
• Bibliography entry Morgan, Casey、Alexei Patrov『自由意志の哲学』翻訳：鈴木真紀、東京：城南大学出版会、2023。〔The Philosophy of Free Will (Chicago, IL: Global Academic Press, 2022).〕

I hope that this will make sense and be accepted as a pull request.