A discrete part of an entire transcription, as identified by the speech recognizer.


@interface SFTranscriptionSegment : NSObject


Use SFTranscriptionSegment to get details about a part of an overall SFTranscription. An SFTranscriptionSegment represents an utterance, which is a vocalized word or group of words that represent a single meaning to the speech recognizer (SFSpeechRecognizer).

You don’t create transcription object segments directly. Instead, you access them from a transcription’s segments property.

A transcription segment includes the following information:

  • The text of the utterance, plus any alternative interpretations of the spoken word.

  • The character range of the segment within the formattedString of its parent SFTranscription.

  • A confidence value, indicating how likely it is that the specified string matches the audible speech.

  • A timestamp and duration value, indicating the position of the segment within the provided audio stream.

  • A voiceAnalytics metric, indicating the likelihood of a voice in a segment, and that voice’s pitch, jitter, and shimmer properties.


Transcribing the Segment


The string representation of the utterance in the transcription segment.


The range information for the transcription segment’s substring, relative to the overall transcription.


An array of alternate interpretations of the utterance in the transcription segment.

Assessing the Recognition Confidence Level


The level of confidence the speech recognizer has in its recognition of the speech transcribed for the segment.

Getting the Audio Timing Information


The start time of the segment in the processed audio stream.


The number of seconds it took for the user to speak the utterance represented by the segment.

Analyzing Voice


An analysis of the transcription segment’s vocal properties.


A collection of vocal analysis metrics.


Inherits From

See Also

Transcription Results


An object containing the partial or final results of a speech recognition request.


A textual representation of the given speech it its entirety, as recognized by the speech recognizer.

Beta Software

This documentation contains preliminary information about an API or technology in development. This information is subject to change, and software implemented according to this documentation should be tested with final operating system software.

Learn more about using Apple's beta software