Timing strategy

REGULAR

The timing of the prompt is independent of the rate at which the subject is actually speaking. In its simplest form each prompt is displayed at regular predefined intervals which will depend on the type of utterance that is to be produced. Alternatively the interval may vary from prompt to prompt depending on the expected (not the actual) time to speak the prompted text, i.e. dependent on the number of words/phonemes in a sentence.

ENDPOINT

The timing of the prompt is totally controlled by the production of utterances. The display of each new prompt is controlled by the detection of the endpoint of the last utterance.

MIXED

The timing of the prompt is controlled by a logical combination of a predetermined interval and the endpoint of an utterance. The display of each new prompt is triggered by whichever is later of the predetermined interval or the endpoint. This means that if a subject is slow the prompting system will slow down, but there is a maximum rate of prompting even for the fastest speaker.