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

# Language Detection

> Language detection API — identify the spoken language of an audio file in a single synchronous HTTP POST.

Language detection identifies the spoken language of an audio file and returns a confidence-scored result. It is a pure classification endpoint — no transcription, diarization, or enrichment data is produced.

|                    | Batch                                          |
| ------------------ | ---------------------------------------------- |
| **Use case**       | Identify the spoken language of an audio file  |
| **Protocol**       | HTTP POST                                      |
| **Languages**      | 100 spoken languages                           |
| **Max file size**  | 100 MB                                         |
| **Audio analyzed** | First 30 seconds only                          |
| **Output**         | ISO 639-1 code, display name, confidence score |

For a side-by-side comparison with the other Modulate capabilities, see [Which API should I use?](/guides/which-api).

## Authentication

Uses the `X-API-Key` header. See [Authentication and rate limits](/guides/authentication).