Voices and languages
SignalWire's cloud platform integrates with leading third-party text-to-speech (TTS) providers. This guide describes supported engines, voices, and languages. Refer to each provider's documentation for up-to-date model details and service information.
Compare providers and models​
SignalWire's TTS providers offer a wide range of voice engines optimized for various applications. Select a provider, model, and voice according to the following considerations:
Cost: When cost-efficiency is the top priority, select a Standard-tier voice from Google Cloud or Amazon Polly. Review our pricing information to learn more.
Language support: Amazon Polly, ElevenLabs, Google Cloud, and OpenAI offer a wide range of supported languages. In addition, all ElevenLabs and OpenAI voices are fully multilingual.
Model quality and realism: All supported providers offer high-quality engines: Google Cloud's WaveNet and Neural2, Amazon Polly Neural, ElevenLabs' Multilingual v2, and Deepgram's Aura are all optimized for voice quality.
SSML support: Google Cloud and Amazon Polly support
SSML
(Speech Synthesis Markup Language) as a string wrapped in <speak> tags.
Consult Google Cloud's SSML docs for details.
Refer to the Amazon Polly docs for more information on
using SSML
and supported SSML tags.
Use voice identifier strings​
Compose voice identifier strings using the <engine>.<voice id> format.
First, select your engine using the gcloud, polly, elevenlabs, or deepgram identifier.
Append a period (.), followed by the specific voice ID from the TTS provider.
Voice identifier strings are case insensitive.
For example,
gcloud.en-US-Neural2-A,
gcloud.en-us-neural2-a, and
GCLOUD.EN-US-NEURAL2-A are equivalent.
For detailed instructions for each provider, consult the voice ID references linked in the Usage column of the below table.
| TTS provider | Engine code | Sample voice ID string | Usage |
|---|---|---|---|
| Amazon Polly | polly | polly.Joanna-Neural | Reference |
| Cartesia | cartesia | cartesia.a167e0f3-df7e-4d52-a9c3-f949145efdab | Reference |
| Deepgram | deepgram | deepgram.aura-asteria-en | Reference |
| ElevenLabs | elevenlabs | elevenlabs.thomas | Reference |
| Google Cloud | gcloud | gcloud.en-US-Casual-K | Reference |
| Microsoft Azure | azure | en-US-AvaNeural | Reference |
| OpenAI | openai | openai.alloy | Reference |
| Rime | rime | rime.luna:arcana | Reference |
Pricing​
Voices are priced according to model in three tiers. Consult our Voice API Pricing for up-to-date pricing information.
Standard
- Google Cloud Standard
- Amazon Polly Standard
Premium
- Google Cloud Neural2, WaveNet, and Journey
- Amazon Polly Neural
- Deepgram Aura
ElevenLabs voices have their own tier.