> For a complete index of all SignalWire documentation pages, fetch https://signalwire.com/docs/llms.txt

# Smallest.ai

> Learn how to use Smallest.ai's Waves Lightning TTS voices with SignalWire AI Voice applications.

Smallest.ai's Waves platform offers fast Lightning text-to-speech voices with especially
strong coverage of Indian languages.

## Models

SignalWire supports the following Waves Lightning models.

| Model                | Description                          |
| -------------------- | ------------------------------------ |
| `lightning_v3.1`     | **Default.** Fast, low-latency model |
| `lightning_v3.1_pro` | Higher-quality model                 |

## Voices

Press play to audition any Smallest.ai voice, then **copy config** to grab the value for SWML or your SDK.

Smallest.ai provides roughly 250 voices in the Waves catalog. A voice's name is its voice ID —
for example, `sophia` (the default, an American English female voice) becomes `smallest.sophia`
in the [voice string](#usage).

Browse the catalog in Smallest.ai's platform and documentation:

#### [Waves platform](https://waves.smallest.ai/)

Preview Waves voices in the browser.

#### [Waves docs](https://waves-docs.smallest.ai/)

Reference for voices, models, and languages.

## Languages

Smallest.ai supports the following languages:

| Language  | Code |
| :-------- | :--- |
| English   | `en` |
| Spanish   | `es` |
| Hindi     | `hi` |
| Bengali   | `bn` |
| Gujarati  | `gu` |
| Kannada   | `kn` |
| Malayalam | `ml` |
| Marathi   | `mr` |
| Odia      | `or` |
| Punjabi   | `pa` |
| Tamil     | `ta` |
| Telugu    | `te` |

Refer to the [Waves docs](https://waves-docs.smallest.ai/)
for the most up-to-date reference to supported languages and voices.

## Usage

A voice identifier string has three parts: the `smallest` engine code, a voice ID, and an optional model.

**Format**: `smallest.<voiceId>:<model>`

* `voiceId` (required): a Waves voice ID (for example, `sophia`); see [Voices](#voices).
* `model` (optional): one of the [models](#models) above. Defaults to `lightning_v3.1`.

**Examples**:

```text
smallest.sophia:lightning_v3.1
smallest.sophia:lightning_v3.1_pro
```

You can also set the model with the separate
[`model`](/docs/swml/reference/ai/languages#use-voice-strings)
parameter of the [`languages`](/docs/swml/reference/ai/languages) SWML method
instead of appending `:model` to the voice string:

```yaml
languages:
- name: English
  code: en-US
  voice: smallest.sophia
  model: lightning_v3.1
```

---

## Build with Smallest.ai on SignalWire

### Create a Space and add credit

If you don't have one yet, you'll need to
[create a SignalWire Space](/docs/platform/signing-up-for-a-space).
Be sure to add some credit to test with.

### Add a new Resource

Navigate to the **Resources** tab in your [SignalWire Dashboard](https://my.signalwire.com) and click **+ Add New** to create a new Resource.

### Create a SWML Script

From the Resources menu, select **SWML Script**.
Name it something fun and recognizable.
Ours is titled Smallest Wizard.

Next, paste the following starter script into the text box, and hit <kbd>Save</kbd>:

```yaml
version: 1.0.0
sections:
  main:
  - ai:
      prompt:
        text: |
          You're Sophia, a voice from Smallest.ai's Waves Lightning TTS engine!
          Introduce yourself, and have a conversation about programmable unified communications on the SignalWire platform.
      languages:
      - name: English
        code: en-US
        voice: smallest.sophia:lightning_v3.1
```

### Buy and assign a phone number

Navigate to the **Phone Numbers** section of the Dashboard's left sidebar menu.

Purchase a phone number and assign it to the desired SWML script.

![A purchased phone number showing assignment to a specified Resource.](https://fdr-prod-docs-files-public.s3.us-east-1.amazonaws.com/signalwire.docs.buildwithfern.com/f0b50511622e76d7be927bd442190e2e41a88745515f22bc727fa5b480e23409/assets/images/dashboard/phone-numbers/assign-resource-voice.webp?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=AKIA6KXJSKKNFOCF7G4B%2F20260811%2Fus-east-1%2Fs3%2Faws4_request&X-Amz-Date=20260811T085756Z&X-Amz-Expires=604800&X-Amz-Signature=4de2d96d346dc8a203789a3ae3970c98c9575b2498f130e4bbc9c0a72ef3037d&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)

### Give it a call!

Call the number you just assigned to chat with your new AI voice application on the phone.

## Next steps with SWML

Now you've deployed your very first SignalWire voice AI application using Smallest.ai voices.
Next, dive deeper into SWML to explore its capabilities!

#### [Methods reference](/docs/swml)

Documentation for all SWML methods

#### [AI in SWML](/docs/swml/guides)

Build advanced AI applications using SignalWire Markup Language

#### [Guides](/docs/swml/guides)

SWML guides and demo applications