Code switching

Transcribe conversations that mix multiple languages in real time or pre-recorded

Code switching handles conversations where speakers switch languages mid-utterance or across turns. Gladia can detect and transcribe the active language dynamically, and annotate results with the detected languages code.

For best accuracy and latency, provide a small set of expected languages. Avoid listing dozens of similar languages.

When to enable it

• Speakers switch languages mid-conversation (e.g. bilingual meetings, multilingual customer support).
• You need the detected language returned per utterance.

When NOT to enable it

• The audio is in a single language — code switching adds unnecessary processing and can introduce misdetections.
• You’ve set exactly one language in languages — in that case code_switching is ignored anyway.

How to use code switching

Enable code switching in the session configuration:

{
  "encoding": "wav/pcm",
  "sample_rate": 16000,
  "bit_depth": 16,
  "channels": 1,
  "language_config": {
    "languages": ["en", "de", "fr"],
    "code_switching": true
  }
}

When enabled, transcript messages include the detected language per utterance and per word. Use the transcript message schema for details.

Do not enable code_switching with an empty languages list. When no languages are specified, the language detector evaluates every utterance against 100+ supported languages, leading to frequent misdetections - especially between similar-sounding languages. If possible, provide a short list of languages you actually expect in the audio.

Recommendations

• Limit the number of languages to those you expect.
• Combine with custom vocabulary per language for domain terms.