Documentation Index
Fetch the complete documentation index at: https://developers.telnyx.com/llms.txt
Use this file to discover all available pages before exploring further.
BCP-47 language code. Default: en-US.
wss://api.telnyx.com/v2/speech-to-text/transcription?language=es
Auto-Detection
Pass multi to enable automatic language detection. The aliases auto and auto_detect are silently mapped to multi.
?language=multi
?language=auto # → multi
?language=auto_detect # → multi
Engine Support
| Engine | Behavior |
|---|
| Deepgram | BCP-47 codes. multi for multi-language mode. |
| Telnyx | Whisper-based. auto_detect disables language hint entirely. |
| Google | BCP-47 codes. |
| Azure | BCP-47 codes. |
| xAI | Language codes such as en, fr, de, and ja. |
| AssemblyAI | Automatic multilingual detection and code switching across supported languages. |
| Speechmatics | Language codes such as en, es. Bilingual packs use Telnyx shorthand (e.g. ar_en) — mapped internally. Does not support auto; defaults to en if unrecognized. |
Supported Languages
For most engines, Telnyx passes the language code directly without validation. The supported set depends on which engine you use. Speechmatics is the exception — Telnyx accepts shorthand codes for bilingual/multilingual packs and maps them to the provider’s language + domain configuration internally.
| Engine | Languages | Reference |
|---|
| Deepgram | 40+ languages. Nova-3 supports multi (10 languages in code-switching mode). Flux: English only. | Deepgram languages |
| Telnyx | Whisper-based. 50+ languages. auto_detect to skip language hint. | — |
| Google | 125+ languages/locales. | Google Cloud STT languages |
| Azure | 100+ languages/locales. | Azure Speech languages |
| xAI | 25 languages, including Arabic, English, French, German, Hindi, Japanese, Korean, Portuguese, Spanish, and Vietnamese. | xAI Voice API |
| AssemblyAI | 6 languages with native multilingual code switching: English, Spanish, German, French, Portuguese, and Italian. | AssemblyAI supported languages |
| Speechmatics | 17+ languages. Standard codes (en, es, cy, sw, etc.) plus Telnyx shorthand for bilingual/multilingual packs (ar_en, cmn_en, en_ms, en_ta, cmn_en_ms_ta). Telnyx maps these internally to Speechmatics language + domain params — do not pass them raw to the provider. | Speechmatics languages |
Common Codes
| Code | Language |
|---|
en or en-US | English (US) |
en-GB | English (UK) |
es | Spanish |
fr | French |
de | German |
pt-BR | Portuguese (Brazil) |
it | Italian |
ja | Japanese |
zh | Chinese (Mandarin) |
hi | Hindi |
ar | Arabic |
ko | Korean |
multi | Multi-language / auto-detect (Deepgram) |
