How transcriptions work when multiple languages are spoken on a call

Nimbata's transcription engine processes the audio of a call and converts it to text.

When a single call contains more than one language, there are a few things worth understanding about how that is handled.

Language detection

Nimbata's transcription service uses automatic language detection.

At the start of processing, the engine analyses the audio and identifies the primary language spoken on the call.

That language is used as the basis for the entire transcription.

What happens when languages switch mid-call

If the conversation switches languages partway through, e.g. starting in English and moving to Spanish, the transcription engine will continue applying the originally detected language to the rest of the audio. This means that sections spoken in a different language may be transcribed inaccurately or appear as garbled text, because the engine is attempting to interpret sounds using the wrong language model.

The result is a transcript that is reliable for the dominant language and unreliable for any secondary language segments.

What this means in practice

• The overall transcript is most accurate when a single language is spoken throughout.
• Short phrases or single words in another language are often handled reasonably well.
• Extended segments in a different language will likely produce low-quality transcription output for those portions.
• AI summaries and keyword spotting derived from the transcript will reflect the same limitations; accuracy drops for content that was not correctly transcribed.

Recommendations

If your calls regularly involve two languages, consider the following:

• Review transcripts manually for calls where a language switch is likely, particularly before using the transcript for coaching, compliance, or reporting.
• Use the AI summary as a cross-check: if the summary seems inconsistent with what you know the call covered, the transcript may have degraded in a multi-language segment.
• Keyword spotting rules work best when configured for the primary language of the call.

Detailed Guide: AI call transcriptions: how to activate transcriptions and summaries

Detailed Guide: How to set up Nimbata AI for automatic call analysis

Detailed Guide: How to set up keyword and phrase spotting

Updated on: 06/05/2026