https://docs.vapi.ai/api-reference/assistants/create#request.body.voice.ElevenLabsVoice.chunkPlan.formatPlan.replacements something like this if youre trying to get 11labs to read numbers slower

replacements = [
    {
                    "type": "regex",
                    "regex": "(\\d)",
                    "value": "$1<break time=\"0.5s\" />"
    }
]