Optionalspeaker?: string | null{
  "text": "Smoke from hundreds of wildfires in Canada is triggering air quality alerts throughout the US.",
  "start": 250,
  "end": 6350,
  "confidence": 0.72412,
  "words": [
    {
      "text": "Smoke",
      "start": 250,
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      "confidence": 0.72412,
      "speaker": null
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    {
      "text": "from",
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      "speaker": null
    },
    {
      "text": "hundreds",
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      "speaker": null
    },
    {
      "text": "of",
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    }
  ],
  "speaker": null
}
The speaker of the sentence if Speaker Diarization is enabled, else null