A Dictionary of Linguistics and Phonetics David Crystal

speech synthesis 447
of participants, genres, codes and other elements. Usage in a language is organized
through the higher-level patterning of speech events. Examples of highly
structured speech events are debates and interviews. Much less structured are
conversations.
speech perception In phonetics and psycholinguistics, a term for the process
whereby a listener extracts a sequence of discrete phonetic and linguistic
units from the continuous acoustic signal of speech. The term also applies to
the study of the neuropsychological mechanisms governing this ability.
speech processing
see speech
speech production In phonetics and psycholinguistics, a term for the activity
of the respiratory, phonatory and articulatory systems during speech, along
with the associated neural programming required for their co-ordination and
use. A contrast is usually drawn with the receptive aspects of spoken communication,
such as speech perception and recognition. See chain (1).
speech recognition In phonetics and computational linguistics, the recognition
of human speech through computer analysis; also called automatic speech
recognition (ASR). The term should not be confused with speaker recognition,
where the aim is to identify the person speaking rather than what is being
said. The task involves the matching of an input acoustic signal with a vocabulary
(of sounds, syllables, words, etc.) stored in the computer’s memory. A
standard technique for matching individual words is to use stored waveforms
(or features/parameters of waveforms) against which an input signal is matched
(‘template matching’). The computer requires a period of training, in which it
receives examples of spoken words provided by (single or multiple) speakers,
and averages these to derive a canonical waveform. The variable rate of
speech inputs needs to be taken into account, most often using the technique of
‘dynamic time warping’, in which segments in the input signal are aligned with
those in the template. The more challenging aim of ASR is to handle continuous
speech. Here the computer is provided with information about typical patterns
of phonetic and phonological segmentation, as well as morphological and
syntactic information. More advanced simulations, such as those provided by
connectionist models, are also used.
speech science(s)
see speech
speech stretcher In instrumental phonetics, a device which presents a slowed
but undistorted recording of speech. It is helpful in identifying sounds which
might otherwise be lost in the speed of normal speech, in studying the transitions
betwen adjacent sounds, and in monitoring such features as intonation.
speech surrogate In linguistics and semiotics, a communication system
which replaces the use of speech. Examples include drum languages and
whistle-speech.
speech synthesis In phonetics and computational linguistics, the process of
generating artificial speech signals, using a model of the linguistically important