curl --request POST \
  --url https://api.example.com/multi_synthesis \
  --header 'Content-Type: application/json' \
  --data '
[
  {
    "accent_phrases": [
      {
        "moras": [
          {
            "text": "<string>",
            "vowel": "<string>",
            "vowel_length": 123,
            "pitch": 123,
            "consonant": "<string>",
            "consonant_length": 123
          }
        ],
        "accent": 123,
        "is_interrogative": false
      }
    ],
    "speedScale": 123,
    "pitchScale": 123,
    "intonationScale": 123,
    "volumeScale": 123,
    "prePhonemeLength": 123,
    "postPhonemeLength": 123,
    "outputSamplingRate": 123,
    "outputStereo": true,
    "pauseLength": 123,
    "pauseLengthScale": 1,
    "kana": "<string>"
  }
]
'

"<string>"