> ## Documentation Index
> Fetch the complete documentation index at: https://docs.unifically.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Gemini 3.8 Flash Lite TTS

> Generate speech with Google's Gemini 3.8 Flash Lite TTS model — fast, high-volume speech with vocal bursts, two-speaker dialogue, and 100+ languages. See parameters, voices, and API examples.

Google's fast, high-volume Gemini 3.8 text-to-speech model for narration, dubbing, read-aloud features, and voice agents. Same request body as Gemini 3.8 Flash TTS. Released September 2026.

## Model

```
google/gemini-3.8-flash-lite-tts
```

## Parameters

| Parameter | Type | Required | Default | Description |
| - | - | - | - | - |
| `input` | string | Yes\* | - | Text to speak. Language is auto-detected (100+ languages). \*Provide exactly one of `input`, `text`, or `dialogue` |
| `text` | string | No | - | Alias for `input` |
| `dialogue` | array | No | - | Dialogue lines as `[{"text", "voice", "speaker"?}, ...]` — see [Multi-Speaker Dialogue](#multi-speaker-dialogue) |
| `voice` | string | No | `alloy` | Voice name — a Gemini voice or an OpenAI-style alias (see [Voices](#voices)) |
| `response_format` | string | No | `mp3` | Output container: `mp3`, `wav`, `pcm`, `opus`, `aac`, `flac` |
| `speed` | number | No | `1.0` | Playback speed multiplier, `0.25`–`4.0` |
| `instructions` | string | No | - | Style directions the voice follows but does not read, e.g. `"speak like a sports commentator"` |
| `language` | string | No | auto | BCP-47 code to pin the output language (see [Languages](#languages)) |
| `speakers` | array | No | - | Two-speaker dialogue config (see [Multi-Speaker Dialogue](#multi-speaker-dialogue)). When set, `voice` is ignored |

## Vocal Bursts

Gemini 3.8 TTS places short non-speech sounds written in **angle brackets** at the exact point they appear in `input`:

```json theme={null}
{ "input": "Did you see that? <laugh> I can't believe it worked. <long pause> Okay, again." }
```

Supported bursts include `<laugh>`, `<sigh>`, `<cough>`, `<breath>`, `<gasp>`, `<short pause>` and `<long pause>`. In two-speaker scripts, listener sounds go between pipes, like `|mhm|` or `|yeah|`. Bursts are performed, not spoken.

The square-bracket tags of Gemini 3.1 Flash TTS (`[whispering]`, `[excited]`) are not part of the 3.8 syntax. Use `instructions` for the overall delivery style instead.

## Multi-Speaker Dialogue

Generate a conversation between **up to 2 voices** in one request. Two equivalent forms are accepted.

**Form 1 — `dialogue` array.** Each line carries its own voice; lines are spoken in order:

```json theme={null}
{
  "dialogue": [
    { "text": "Did the deploy finish?", "voice": "onyx", "speaker": "Joe" },
    { "text": "Yes, all green — we are live!", "voice": "nova", "speaker": "Jane" },
    { "text": "Great news.", "voice": "onyx", "speaker": "Joe" }
  ]
}
```

`speaker` is optional — lines sharing a voice are treated as the same speaker automatically. If every line uses the same voice, the result is ordinary single-voice speech.

**Form 2 — script plus `speakers` map.** Write the script in `input` with speaker names, and map each name to a voice:

```json theme={null}
{
  "input": "Joe: Did the deploy finish? Jane: Yes, all green — we are live!",
  "speakers": [
    { "speaker": "Joe", "voice": "onyx" },
    { "speaker": "Jane", "voice": "Leda" }
  ]
}
```

Speaker names must match the names used in `input` exactly. Both forms are limited to 2 distinct voices — a third voice is rejected with a `400`.

## Voices

30 prebuilt voices. Use either the Gemini name or the OpenAI-style alias in `voice` and `speakers[].voice`:

| Voice | Style | OpenAI alias |
| - | - | - |
| `Achernar` | Soft | - |
| `Achird` | Friendly | - |
| `Algenib` | Gravelly | - |
| `Algieba` | Smooth | - |
| `Alnilam` | Firm | - |
| `Aoede` | Breezy | `fable` |
| `Autonoe` | Bright | - |
| `Callirrhoe` | Easy-going | `sage` |
| `Charon` | Informative | `onyx` |
| `Despina` | Smooth | - |
| `Enceladus` | Breathy | - |
| `Erinome` | Clear | - |
| `Fenrir` | Excitable | `ash` |
| `Gacrux` | Mature | - |
| `Iapetus` | Clear | - |
| `Kore` | Firm | `alloy` |
| `Laomedeia` | Upbeat | - |
| `Leda` | Youthful | `nova` |
| `Orus` | Firm | `verse` |
| `Puck` | Upbeat | `echo` |
| `Pulcherrima` | Forward | - |
| `Rasalgethi` | Informative | - |
| `Sadachbia` | Lively | - |
| `Sadaltager` | Knowledgeable | - |
| `Schedar` | Even | - |
| `Sulafat` | Warm | `coral` |
| `Umbriel` | Easy-going | `ballad` |
| `Vindemiatrix` | Gentle | - |
| `Zephyr` | Bright | `shimmer` |
| `Zubenelgenubi` | Casual | - |

## Languages

Language is **auto-detected** from `input` (100+ languages). Set `language` only to force a specific locale:

| Code | Language |
| - | - |
| `ar-EG` | Arabic (Egyptian) |
| `bn-BD` | Bengali |
| `de-DE` | German |
| `en-IN` | English (India) |
| `en-US` | English (US) |
| `es-US` | Spanish (US) |
| `fr-FR` | French |
| `hi-IN` | Hindi |
| `id-ID` | Indonesian |
| `it-IT` | Italian |
| `ja-JP` | Japanese |
| `ko-KR` | Korean |
| `mr-IN` | Marathi |
| `nl-NL` | Dutch |
| `pl-PL` | Polish |
| `pt-BR` | Portuguese (Brazil) |
| `ro-RO` | Romanian |
| `ru-RU` | Russian |
| `ta-IN` | Tamil |
| `te-IN` | Telugu |
| `th-TH` | Thai |
| `tr-TR` | Turkish |
| `uk-UA` | Ukrainian |
| `vi-VN` | Vietnamese |

## Output Formats

| Format | Description |
| - | - |
| `mp3` | MP3 (default) |
| `wav` | WAV, 24kHz 16-bit |
| `pcm` | Raw PCM, 24kHz 16-bit mono |
| `opus` | Opus in an Ogg container |
| `aac` | AAC (ADTS) |
| `flac` | FLAC lossless |

## Resources

List voices and languages from the [Resources API](/api-reference/resources):

```
GET /v1/resources/google/tts/voices
GET /v1/resources/google/tts/languages
```

## Example

```bash theme={null}
curl -X POST https://api.unifically.com/v1/tasks \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -d '{
    "model": "google/gemini-3.8-flash-lite-tts",
    "input": {
      "input": "Your order has shipped and arrives tomorrow.",
      "voice": "nova",
      "response_format": "mp3",
      "instructions": "Speak cheerfully, like a friendly support agent."
    }
  }'
```

## Response

```json theme={null}
{
  "code": 200,
  "success": true,
  "data": {
    "task_id": "abc123def456",
    "status": "processing"
  }
}
```

## Completed Response

Poll `GET /v1/tasks/{task_id}` until `status` is `completed`:

```json theme={null}
{
  "code": 200,
  "success": true,
  "data": {
    "task_id": "abc123def456",
    "status": "completed",
    "output": {
      "audio_url": "https://files.unifically.com/audio/abc123.mp3"
    }
  }
}
```

<Note>
  **Volume discounts** are available for almost all models. Reach out at [contact@unifically.com](mailto:contact@unifically.com) to discuss custom pricing.
</Note>


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