> ## AI Agent Context
> Get the complete documentation index at: https://aistudio.google.com/llms.txt
> Use this file to discover all available pages.
> For the full documentation in a single file, fetch: https://aistudio.google.com/llms-full.txt

# Gemini 3.8 Flash TTS

Gemini 3.8 Flash TTS (`gemini-3.8-flash-tts`) is Google's flagship creative
text-to-speech model, engineered for studio-grade voice fidelity, expressive
acting, authentic regional accents, and rock-solid long-form multi-turn
stability.

{% button href="https://aistudio.google.com?model=gemini-3.8-flash-tts" variant="ais" %}Try in Google AI Studio{% /button %}

## Overview and capabilities  {% id="overview-and-capabilities" %}

Gemini 3.8 Flash TTS sets a new benchmark for expressive audio generation:

*   **High acoustic fidelity and acting nuance:** Delivers rich emotional range,
  natural cadence, and precise adherence to turn-level `style` directions and
  inline vocal events (`<laugh>`, `<sigh>`, `<short pause>`).
*   **Long-form multi-turn stability:** Maintains consistent voice identity,
  timbre, volume, and acoustic room tone across extended dialogues and
  multi-minute narrations without voice drift.
*   **Authentic regional accents and pronunciation:** Supports regional accents
  and minority dialects.
*   **Full voice ecosystem support:** Works seamlessly with prebuilt voices, the
  Extended Voice Library (`GET /v1beta/voices`), custom
  [Voice design](/docs/voice-design) personas, and
  [Voice replication](/docs/voice-replication) (persistent stored voices by
  default, plus optional stateless keys). You can also design and replicate
  voices interactively in
  [Google AI Studio](https://aistudio.google.com/generate-speech).

Visit the [Text-to-speech](/docs/speech-generation) guide for full coverage of
features, prompting best practices, and code examples.

## When to use which TTS model  {% id="when-to-use-which-tts-model" %}

Both Gemini 3.8 TTS models share the same API schema and prompting structure.
Choose the model that fits your workload:

| Feature / workload | Gemini 3.8 Flash TTS (`gemini-3.8-flash-tts`) | Gemini 3.8 Flash-Lite TTS (`gemini-3.8-flash-lite-tts`) |
| :--- | :--- | :--- |
| **Primary strength** | Maximum voice fidelity, acting nuance, and dialect coverage | High throughput, low latency, and cost efficiency |
| **Best use cases** | Audiobooks, studio narration, complex multi-speaker dialogue, heavy vocal-burst acting, difficult pronunciation, regional dialects | High-volume production, real-time voice agent cascades, read-aloud features, voice replication, everyday single-speaker generation |
| **Supported languages** | 130 languages | 101 languages |
| **Recommended replacement for** | New flagship creative tier | `gemini-3.1-flash-tts-preview` |

## Migration guide  {% id="migration-guide" %}

If you are migrating from `gemini-3.1-flash-tts-preview` or earlier Gemini TTS
models, update your requests for the Gemini 3.8 TTS schema:

1.  **Move turn-level directions into `speech_metadata`:** Gemini 3.8 TTS treats
  input text strictly as a verbatim transcript. Inline text directions like
  `"Say cheerfully: Hello!"` or `"Speaker 1: Hello!"` may be spoken aloud.
  Move sustained delivery instructions (`style`) and speaker labels
  (`speaker`) into structured metadata:  *   **Interactions API:** Attach an annotation with `"type":
"speech_metadata"`, `"speaker"`, and `"style"` to each text content
    block.
  *   **GenerateContent API:** Attach `"speech_metadata": {"speaker": "...",
"style": "..."}` to each `part`.

2.  **Use angle-bracket inline tags only for point-in-time vocal events:** Keep
  momentary non-speech vocalizations and pauses inline in the transcript using
  angle brackets (such as `<laugh>`, `<sigh>`, `<cough>`, `<breath>`, or
  `<short pause>`). Put delivery styles like whispering in
  `speech_metadata.style`.
3.  **Specify `speaker` on every turn in multi-speaker requests:** Every turn in
  a multi-speaker request must explicitly include `speaker` inside
  `speech_metadata` matching one of the configured speakers.
4.  **Design personas upfront with Voice design:** Replace long legacy Audio
  Profile / Director's Notes blocks with a custom voice created in
  [Voice design](/docs/voice-design), then carry that `voice_...` ID through
  your TTS requests with minimal or empty `style` strings.
5.  **Account for default WAV (`audio/wav`) output on unary requests:** Unlike
  `gemini-3.1-flash-tts-preview` and earlier TTS models (which returned
  headerless raw PCM `audio/l16` by default), Gemini 3.8 TTS returns WAV audio
  (`audio/wav` / `AUDIO_WAV`) with a standard RIFF header by default for unary
  requests.  *   If your code previously wrapped raw PCM bytes in a WAV header (for
    example, using Python's `wave` module or `ffmpeg`), remove the manual
    header wrapper and write the returned bytes directly to a `.wav` file.
  *   If your pipeline requires headerless raw PCM, mu-law, or A-law audio,
    explicitly set `response_format.mime_type` to `"audio/l16"`,
    `"audio/mulaw"`, or `"audio/alaw"` (for example, `{"response_format":
{"type": "audio", "mime_type": "audio/l16"}}` in the Interactions API,
    or `AUDIO_L16`, `AUDIO_MULAW`, or `AUDIO_ALAW` in `generateContent`).
    See
    [Audio output formats](/docs/speech-generation#audio-output-formats).


## gemini-3.8-flash-tts  {% id="gemini-38-flash-tts" %}

{% table variant="model" %}
  * Property
  * Description

  ---

  *     {% section class="model-property" %}
  {% icon name="id_card" /%}Model code

    {% /section %}

  * `gemini-3.8-flash-tts`

  ---

  *     {% section class="model-property" %}
  {% icon name="save" /%}Supported data types

    {% /section %}

  *     **Inputs** Text

    **Output** Audio


  ---

  *     {% section class="model-property" %}
  {% icon name="token_auto" /%}Token limits{% sup %}[[*]](/docs/tokens){% /sup %}

    {% /section %}

  *     **Input token limit** 8,192

    **Output token limit** 16,384 (Gemini API serving limit)


  ---

  *     {% section class="model-property" %}
  {% icon name="handyman" /%}Capabilities

    {% /section %}

  *     {% section class="three-column-grid" %}
  {% section %}
  **Audio generation**

  {% badge type="supported" /%}

  {% /section %}

  {% section %}
  **Batch API**

  {% badge type="supported" /%}

  {% /section %}

  {% section %}
  **Caching**

  {% badge type="not-supported" /%}

  {% /section %}

  {% section %}
  **Code execution**

  {% badge type="not-supported" /%}

  {% /section %}

  {% section %}
  **File search**

  {% badge type="not-supported" /%}

  {% /section %}

  {% section %}
  **Flex inference**

  {% badge type="supported" /%}

  {% /section %}

  {% section %}
  **Function calling**

  {% badge type="not-supported" /%}

  {% /section %}

  {% section %}
  **Grounding with Google Maps**

  {% badge type="not-supported" /%}

  {% /section %}

  {% section %}
  **Image generation**

  {% badge type="not-supported" /%}

  {% /section %}

  {% section %}
  **Live API**

  {% badge type="not-supported" /%}

  {% /section %}

  {% section %}
  **Priority inference**

  {% badge type="supported" /%}

  {% /section %}

  {% section %}
  **Search grounding**

  {% badge type="not-supported" /%}

  {% /section %}

  {% section %}
  **Structured outputs**

  {% badge type="not-supported" /%}

  {% /section %}

  {% section %}
  **Thinking**

  {% badge type="not-supported" /%}

  {% /section %}

  {% section %}
  **URL context**

  {% badge type="not-supported" /%}

  {% /section %}

    {% /section %}


  ---

  *     {% section class="model-property" %}
  {% icon name="123" /%}Versions

    {% /section %}

  *     Read the [model version patterns](/docs/models#model-versions) for more details.

    *   `gemini-3.8-flash-tts`


  ---

  *     {% section class="model-property" %}
  {% icon name="calendar_month" /%}Latest update

    {% /section %}

  * September 2026

  ---

  *     {% section class="model-property" %}
  {% icon name="paid" /%}Pricing

    {% /section %}

  * [Pricing](/docs/pricing#gemini-3.8-flash-tts)
{% /table %}

## Supported languages  {% id="supported-languages" %}

`gemini-3.8-flash-tts` detects the input language automatically and supports
**over 130 languages**:

| Language | Language | Language |
| :--- | :--- | :--- |
| Acehnese (Arab script) | Greek | Nepali (individual language) |
| Afrikaans | Guarani | Nigerian Fulfulde |
| Akan | Gujarati | North Azerbaijani |
| Amharic | Haitian Creole | Northern Sotho |
| Armenian | Halh Mongolian | Northern Uzbek |
| Assamese | Hausa | Norwegian Bokmål |
| Awadhi | Hebrew | Norwegian Nynorsk |
| Balinese | Hindi | Nyanja |
| Bangla | Hungarian | Occitan |
| Banjar (Arab script) | Icelandic | Odia (individual language) |
| Banjar (Latn script) | Igbo | Pangasinan |
| Bashkir | Iloko | Persian (Afghanistan) |
| Basque | Indonesian | Polish |
| Belarusian | Iranian Persian | Portuguese |
| Bemba | Italian | Punjabi |
| Bhojpuri | Japanese | Romanian |
| Bosnian | Javanese | Russian |
| Buginese | Kabyle | Santali |
| Bulgarian | Kamba | Serbian |
| Burmese | Kannada | Sindhi |
| Cantonese | Kashmiri (Arab script) | Sinhala |
| Catalan | Kashmiri (Deva script) | Slovak |
| Cebuano | Kazakh | Slovenian |
| Central Kurdish | Khmer | Somali |
| Chhattisgarhi | Kikuyu | South Azerbaijani |
| Chinese (Hans script) | Kinyarwanda | Southern Pashto |
| Chinese (Hant script) | Kongo | Southern Sotho |
| Crimean Tatar | Korean | Spanish |
| Croatian | Kyrgyz | Standard Arabic (Arab script) |
| Czech | Lao | Standard Arabic (Latn script) |
| Danish | Latgalian | Standard Latvian |
| Dutch | Lingala | Standard Malay |
| Dyula | Lithuanian | Swahili (individual language) |
| Dzongkha | Luxembourgish | Swati |
| Egyptian Arabic | Macedonian | Swedish |
| English | Magahi | Tajik |
| Estonian | Maithili | Tamil |
| Filipino | Malayalam | Telugu |
| Finnish | Maltese | Thai |
| French | Manipuri | Tigrinya |
| Galician | Marathi | Tosk Albanian |
| Ganda | Minangkabau (Arab script) | Turkish |
| Georgian | Minangkabau (Latn script) | Uyghur |
| German | Mizo | Vietnamese |