sendtext.cs

[Function("SendSpeechTestFunction")]
public async Task<HttpResponseData> SendSpeech([HttpTrigger(AuthorizationLevel.Anonymous, "post", Route = "send/text")] HttpRequestData request)
{
    var model = await request.ReadFromJsonAsync<SendSpeedRequestModel>();
    var callAutomationClient = new CallAutomationClient(_configuration["AcsConnectionString"]);
    var callConnection = callAutomationClient.GetCallConnection(model.CallConnectionId);
    var callMedia = callConnection.GetCallMedia();

    var playSource = new TextSource(model.Text)
    {
        SourceLocale = "en-US",
        CustomVoiceEndpointId = _configuration["CustomVoiceEndpointId"],
        VoiceName = _configuration["NeuralVoiceName"]
    };

    await callMedia.PlayToAllAsync(playSource);
    return request.CreateResponse(HttpStatusCode.Accepted);
}