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

# Languages

> Configure auto-detection or constrain transcription to specific languages.

Use `languages` to control language detection.

## Auto-detect

Omit `languages` or pass `"auto"`:

```bash theme={null}
-F 'languages="auto"'
```

VoiceOS lets ASR detect from all supported languages.

## Force one language

Pass a single language code:

```bash theme={null}
-F 'languages="en"'
```

This maps internally to the ASR `language` option.

## Detect within a set

Pass a JSON array:

```bash theme={null}
-F 'languages=["en","ja","es"]'
```

This maps internally to `enabledLanguages`, allowing ASR to detect only within that set.

## Why there is no default language

VoiceOS intentionally avoids `default_language`.

If a caller wants one language, they should pass that language. If a caller wants detection, they should use `"auto"` or an array of allowed languages. This keeps the API contract simple and avoids hidden fallback behavior.

## Recommended defaults

| Product behavior          | `languages`           |
| ------------------------- | --------------------- |
| General voice agent       | `"auto"`              |
| English-only assistant    | `"en"`                |
| Bilingual assistant       | `["en", "ja"]`        |
| Compliance-bound workflow | one explicit language |