curl --request GET \
  --url 'https://api.inworld.ai/tts/v1/voices?filter=language=en' \
  --header 'Authorization: Basic <api-key>'

{
  "voices": [
    {
      "languages": [
        "en"
      ],
      "voiceId": "Alex",
      "displayName": "Alex",
      "description": "Energetic and expressive mid-range male voice, with a mildly nasal quality",
      "tags": [
        "male",
        "energetic",
        "expressive",
        "mid-range"
      ]
    },
    {
      "languages": [
        "en"
      ],
      "voiceId": "Ashley",
      "displayName": "Ashley",
      "description": "A warm, natural female voice",
      "tags": [
        "female",
        "warm",
        "natural"
      ]
    },
    {
      "languages": [
        "en"
      ],
      "voiceId": "Dennis",
      "displayName": "Dennis",
      "description": "Middle-aged man with a smooth, calm and friendly voice",
      "tags": [
        "male",
        "middle-aged",
        "smooth",
        "calm",
        "friendly"
      ]
    }
  ]
}