Azure Speech TTS Integration

Azure Cognitive Services Speech is the strongest TTS option for enterprises already invested in the Microsoft ecosystem. It offers the widest selection of neural voices (400+ across 140 languages), full SSML support for fine-grained prosody control, and deployment within Azure’s compliance boundary. Choose Azure Speech when you need enterprise-grade voice synthesis with SSML customization or when regulatory requirements demand that audio processing stays within Azure. This guide covers integrating Azure Speech as a TTS provider within Beluga AI.

Overview

The Azure Speech integration uses the voice/tts package registry to create a TTS provider backed by Azure Cognitive Services. It supports neural voices, SSML markup for prosody control, and multiple output audio formats.

Prerequisites

• Go 1.23 or later
• Azure account with Speech Services resource
• Azure subscription key and region

Installation

go get github.com/lookatitude/beluga-ai

Set environment variables:

export AZURE_SPEECH_KEY="your-key"
export AZURE_SPEECH_REGION="eastus"

Configuration

Create an Azure TTS provider:

package main

import (
    "context"
    "fmt"
    "log"
    "os"

    "github.com/lookatitude/beluga-ai/voice/tts"
)

func main() {
    ctx := context.Background()

    config := tts.Config{
        Provider: "azure",
        APIKey:   os.Getenv("AZURE_SPEECH_KEY"),
        Region:   os.Getenv("AZURE_SPEECH_REGION"),
        Voice:    "en-US-JennyNeural",
    }

    provider, err := tts.NewProvider(ctx, "azure", config)
    if err != nil {
        log.Fatalf("Failed to create provider: %v", err)
    }

    text := "Hello from Azure Cognitive Services."
    audio, err := provider.GenerateSpeech(ctx, text)
    if err != nil {
        log.Fatalf("Speech generation failed: %v", err)
    }

    fmt.Printf("Generated %d bytes of audio\n", len(audio))
}

Usage

SSML Support

Use SSML for advanced voice control including prosody, pitch, and rate:

ssml := `<speak version="1.0" xmlns="http://www.w3.org/2001/10/synthesis" xml:lang="en-US">
    <voice name="en-US-JennyNeural">
        <prosody rate="fast" pitch="high">
            Hello, this is SSML text-to-speech.
        </prosody>
    </voice>
</speak>`

audio, err := provider.GenerateSpeechFromSSML(ctx, ssml)
if err != nil {
    log.Fatalf("SSML generation failed: %v", err)
}

Observability

Add OpenTelemetry tracing:

import (
    "go.opentelemetry.io/otel"
    "go.opentelemetry.io/otel/attribute"
    "go.opentelemetry.io/otel/trace"
)

tracer := otel.Tracer("beluga.voice.tts.azure")
ctx, span := tracer.Start(ctx, "azure.generate",
    trace.WithAttributes(
        attribute.String("voice", config.Voice),
        attribute.String("region", config.Region),
    ),
)
defer span.End()

Configuration Reference

Option	Description	Default	Required
APIKey	Azure Speech key	-	Yes
Region	Azure region	eastus	No
Voice	Voice name	en-US-JennyNeural	No
Language	Language code	en-US	No

Troubleshooting

Invalid subscription key

Verify the key in the Azure portal under your Speech Services resource. Ensure the key matches the configured region.

Region not found

Use a valid Azure region such as eastus, westus2, or westeurope. The region must match the region where your Speech Services resource was created.

Advanced Topics

Production Deployment

• Use neural voices for the best audio quality
• Leverage SSML for fine-grained prosody and style control
• Monitor usage through the Azure portal for cost management
• Deploy the Speech Services resource in a region close to your users
• Implement retry logic for transient Azure API failures

Related Resources

• ElevenLabs Streaming API
• Voice Services Overview