How speaker identifiers work

Understand how the Speechmatics engine produces speaker identifiers and how they differ from diarization labels.

Understand how the Speechmatics engine produces speaker identifiers and how they differ from diarization labels.

Diarization assigns per-session labels: S1, S2, S3. These labels last only for one session. The person who is S1 in one session may be S2 in the next. Speaker identifiers give those speakers durable memory. During a session the engine builds a voice fingerprint for each speaker, and you can save those fingerprints as identifiers. Supplied to a later session, the engine attributes matching voices to a name you chose, such as Sam instead of S1.

What a speaker identifier is

A speaker identifier is a voice fingerprint the engine produces once diarization is enabled. It is a string, unique per Speechmatics account. Identifiers do not work across accounts: a fingerprint created under one account cannot be used under another.

Speaker identifiers and known_speakers are available in realtime and batch speaker identification. The exact names vary by client.

A speaker can accumulate more than one identifier over time, as the engine hears them in different conditions. A saved profile is therefore a name plus a list of identifiers, and you extend that list each time you encounter the speaker. More identifiers improve recognition.

Speaker memory compared with speaker identification

Speaker memory and speaker identification use the same identifiers for different jobs.

Capability	When identifiers are captured	Typical use
Speaker identification	Enrolled ahead of time from short audio clips	Apply known speakers in batch or realtime transcription
Speaker memory	Captured live during an agent session	Recognize a returning speaker without prior enrollment

Next steps

• Speaker memory for voice agents — capture and reuse identifiers across sessions.
• Speaker identification — enroll known speakers ahead of time.