> For the complete documentation index, see [llms.txt](https://docs.qolaba.ai/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.qolaba.ai/model-reference/speech-models.md).

# Speech Models

Qolaba's Speech Generation is powered by **Google's Gemini TTS** — two models offering different trade-offs between speed, quality, and credit cost. Both models support single-speaker narration and multi-speaker dialogue generation with customizable voice, accent, and delivery style.

***

### Available Models

| Model                | Speed           | Quality                              | Best For                                                                 |
| -------------------- | --------------- | ------------------------------------ | ------------------------------------------------------------------------ |
| **Gemini Flash TTS** | Fast            | Good                                 | Script drafting, quick iterations, testing voice and accent combinations |
| **Gemini Pro TTS** ⭐ | Slightly slower | Higher — more expressive and natural | Final production output, client-ready audio, publishing                  |

{% hint style="info" %}
Test your script, voice selection, and accent configuration with Flash TTS first. Switch to Pro TTS for the final generation only. This approach saves credits without compromising final output quality.
{% endhint %}

***

### Model Capabilities

Both models share the same core capabilities:

| Capability                     | Flash TTS        | Pro TTS          |
| ------------------------------ | ---------------- | ---------------- |
| **Single Speaker Mode**        | ✓                | ✓                |
| **Multi-Speaker Mode**         | ✓                | ✓                |
| **Voice library**              | 30+ voices       | 30+ voices       |
| **Accent & dialect selection** | ✓                | ✓                |
| **Style instructions**         | ✓                | ✓                |
| **Multi-language support**     | ✓                | ✓                |
| **Max script length**          | 5,000 characters | 5,000 characters |

***

### Voice Library

Both models provide access to a library of 30+ distinct voice profiles. Each voice has a unique combination of tone, pitch, energy, and speaking style. Click any voice in the interface to hear a preview before selecting.

**Available Voices**

| Voice             | Character                      |
| ----------------- | ------------------------------ |
| **Zephyr**        | Bright, clear, and energetic   |
| **Puck**          | Upbeat and playful             |
| **Charon**        | Informative and measured       |
| **Kore**          | Firm and confident             |
| **Fenrir**        | Excitable and expressive       |
| **Aoede**         | Smooth and warm                |
| **Leda**          | Youthful and approachable      |
| **Orus**          | Clear and neutral              |
| **Schedar**       | Gravelly and deep              |
| **Gacrux**        | Soft and gentle                |
| **Pulcherrima**   | Calm and composed              |
| **Achird**        | Conversational and natural     |
| **Zubenelgenubi** | Professional and authoritative |
| **Vindemiatrix**  | Storytelling and expressive    |
| **Sadachbia**     | Warm and personable            |
| **Sadaltager**    | Crisp and articulate           |
| **Sulafat**       | Rich and resonant              |

{% hint style="info" %}
The full voice library is accessible directly in the [Speech Generation workspace](https://www.qolaba.ai/ai-speech-generator/text-to-speech). Click any voice name to preview it before selecting.
{% endhint %}

***

### Accent & Dialect Support

The output language is determined automatically by the language of your input script — write in any language and the audio is generated in that language. Accent selection refines pronunciation for languages with multiple regional dialects.

#### **Available Accents by Language**

| Language       | Available Dialects                              |
| -------------- | ----------------------------------------------- |
| **English**    | United States, United Kingdom, India, Australia |
| **French**     | France, Canada                                  |
| **Spanish**    | Spain, Latin America                            |
| **Arabic**     | Egypt, Global                                   |
| **Mandarin**   | China, Taiwan                                   |
| **Hindi**      | India                                           |
| **Portuguese** | Brazil, Portugal                                |
| **German**     | Germany, Austria                                |
| **Japanese**   | Japan                                           |
| **Korean**     | Korea                                           |

{% hint style="info" %}
The output language always follows the language of your input text. Accent selection narrows the regional dialect within that language — it does not override the language itself.
{% endhint %}

***

### Style Instructions

Both models support style instructions — a plain-language description of the desired delivery tone and manner entered in the **Style Prompt** field.

**Examples:**

<table><thead><tr><th width="273.52734375">Intent</th><th>Style Instruction</th></tr></thead><tbody><tr><td>Warm and conversational</td><td><em>"Speak warmly and conversationally, like talking to a friend"</em></td></tr><tr><td>Professional narration</td><td><em>"Clear, professional, and authoritative tone"</em></td></tr><tr><td>Energetic marketing</td><td><em>"Enthusiastic and high-energy delivery"</em></td></tr><tr><td>Calm instructional</td><td><em>"Calm, slow-paced, and easy to follow"</em></td></tr><tr><td>Storytelling</td><td><em>"Engaging narrative style with natural pauses and expression"</em></td></tr></tbody></table>

***

### Flash TTS vs. Pro TTS — When to Use Each

#### **Use Flash TTS when:**

* Testing a new script for the first time
* Validating voice, accent, and style combinations before final generation
* Producing audio for internal use, drafts, or non-published content
* Working at high volume where credit efficiency matters

#### **Use Pro TTS when:**

* Generating final production audio for publishing
* Delivering client-ready voiceovers, ads, or podcast content
* The naturalness and expressiveness of the voice matters for the audience
* Multi-speaker dialogue needs to sound as realistic as possible