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

# Voice optimization for natural speech

> Improve agent voice quality in Thoughtly with accents, language selection, speaking-speed controls, and pronunciation overrides for tricky words and names.

export const NextSection = ({title, icon, href, description}) => <div>
		<br />
		<Card title={title} icon={icon} href={href} horizontal="true">
			{description}
		</Card>
	</div>;

## Match Accent to Market

Pick a voice accent that matches your caller's region. This improves trust and comprehension.

| Market            | Recommended accent   |
| ----------------- | -------------------- |
| **North America** | US English           |
| **Europe**        | UK English           |
| **ANZ**           | Australian English   |
| **Mexico**        | Mexican Spanish      |
| **Spain**         | Castilian Spanish    |
| **Argentina**     | Argentine Spanish    |
| **Brazil**        | Brazilian Portuguese |
| **Portugal**      | European Portuguese  |

Test with native speakers in your target market before going live.

## Language

Each agent has a **Language** dropdown in the conversation settings sidebar. Pick the language, then assign a voice in that same language. Mismatched voice/language pairs cause noticeable pronunciation problems.

Thoughtly supports 36 languages. If you need a language that is not listed in the dropdown, [contact support](/support/getting-help).

To serve callers in multiple languages, create a separate agent per language with matching voice and [Genius](/genius/getting-started) knowledge base.

## Speed (Cartesia)

Cartesia voices have a **Voice Speed** slider in the **Presence** section of the Agent Builder sidebar. The slider runs from 0 (slowest) to 100 (fastest), with 50 as the default. Small adjustments of 10 points are noticeable. The slider is disabled when a non-Cartesia voice is active.

## Volume (Coming Soon)

A volume slider for Cartesia voices is in development and will appear alongside the speed control in Presence settings.

## Pronunciation Fixes

If your agent mispronounces names, brands, or industry terms:

1. **Phonetic spelling in prompts**: write "Thought-lee" instead of "Thoughtly"
2. **Genius pronunciation guide**: add entries to your [Genius](/genius/getting-started) knowledge base with the correct spoken form
3. **Voice cloning**: [clone a voice](/agents/voice-cloning) that naturally handles your domain vocabulary

<NextSection title="Bring Your Own Key (BYOK)" icon="key" href="/agents/voice-byok" description="Connect your own voice provider key for personal voices, usage limits, and pricing ->" />