Michael Ashby & John Maidment

Introducing Phonetic Science

Glossary



Accented syllable: A syllable made prominent by pitch (commonly a pitch peak). In English intonation, a stressed syllable made prominent by being accompanied by the start of a new trend in the pitch contour of the utterance.

Active articulator: The articulator which moves to form a constriction in the vocal tract. For example, in palatal sounds the active articulator is the front of the tongue which moves towards the hard palate.

Advanced: Produced slightly further forward in the vocal tract. For instance, the first consonant in the English word keen is an advanced velar and is produced with a closure towards the front of the velum.

Affricate: A consonant sound produced with a complete closure between two articulators and with velic closure preventing air escaping via the nasal cavity. The articulators part relatively slowly and the compressed air escaping between them becomes turbulent resulting in audible friction noise. [ts dZ kx] are examples of affricates.

Air-stream mechanism: One of a number of ways in which airflow can be created in the vocal tract for the purpose of producing speech sounds.

Allotone: A pitch configuration considered as a positional variant of a toneme. For example, Modern Standard Chinese Tone 3 has a terminal rise in pitch when found before a pause, but lacks this terminal rise when not before a pause. These two pitch configurations can be regarded as allotones of the Tone 3 toneme.

Allophone: A speech sound considered as a positional variant of a phoneme. So, for instance, in Spanish the two sounds [b] and [B] are allophones of the phoneme /b/. The bilabial fricative [B] occurs word-internally between vowels and the plosive [b] occurs in other environments.

Alphabetic writing system: A system of writing, like that used for English, where the symbols used represent the individual vowels and consonants of the language.

Alternation: The situation where a word or word-part turns up in different phonological forms in different environments. For example, the English plural ending s is /s/ if the preceding sound is voiceless, as in books /bUks/, but it is /z/ if the preceding sound is voiced, as in dogs /dQgz/.

Alveolar ridge: The front part of the roof of the mouth, just behind the upper front teeth.

Alveolar: The name of a place of articulation. The active articulator is the tip or blade of the tongue. The passive articulator is the alveolar ridge. [t s n] are examples of alveolar sounds.

Ambient noise: Noise in the environment which may interfere with the recording of sounds.

Amplitude: A measure of the up-and-down extent of a waveform (as distinct from its frequency). For a sound wave, the extent of pressure variation above or below atmospheric pressure.

Aperiodic: Of a waveform, one which does not have a regular repeating pattern.

Approximant: A consonant sound made with a constriction between two articulators which is not narrow enough to cause air turbulence. [w l j] are examples of approximants.

Articulation: A constriction of the vocal tract.

Articulators: The parts of the vocal tract involved in the production of speech sounds: the lips, teeth, tongue, alveolar ridge, hard palate, soft palate, uvula, pharyngeal wall and vocal folds.

Arytenoid cartilages: Two small cone-shaped cartilages which sit on the upper surface of the cricoid cartilage. The vocal folds are attached at the back to the arytenoids and the positioning of the cartilages is largely responsible for the position of and tension of the folds.

Aspiration: Weak friction noise heard on the release of a plosive sound. The noise is caused by air moving at high speed through the vocal tract. Aspiration is associated with plosives which have a long voice onset time.

Assimilation: A phonological process which involves a change in a speech sound to make it more similar to some sound in its environment. An example from English: the word ten which is /ten/ in most environments may become /tem/ if the following word begins with a bilabial consonant, as for example in the phrase ten books, which may be pronounced /tem bUks/.

Audiogram: A graph showing the sensitivity of a human subject to sounds at various frequencies.

Audiometer: A device capable of producing tones of precise frequency and intensity which is used to test human sensitivity to sound at various frequencies.

Auditory canal: the channel which leads from the outer part of the ear to the eardrum.

Back (of tongue): The part of the tongue which lies below the soft palate when the tongue is at rest.

Bilabial: The name of a place of articulation. The articulators are the upper and lower lips. [p b m] are examples of bilabial sounds.

Binary: Of phonological features, taking one of two opposite values. So for example, speech sounds may be classified as [+nasal] if they are made with the velum lowered or [-nasal] if not.

Blade (of tongue): The part of the tongue which lies below the alveolar ridge when the tongue is at rest.

Breathy voice: A type of phonation in which the pattern of vocal fold vibration allows the escape of relatively large amounts of air in each cycle of vibration, producing audible noise along with voicing.

Cardinal vowels: A set of agreed vowel qualities used as a reference for the purposes of describing vowels encountered in speech.

Categorical perception: A characteristic of the perception of certain speech sounds. Sounds are said to be perceived categorically if there is a sharp cross-over from one perceptual category to another and if, in addition, human listeners are unable to distinguish between acoustically different sounds which fall in the same category.

Click: A sound produced with an ingressive velaric airstream mechanism.

Coarticulation: The adjustments made to the articulation of a speech sound under the influence of neighbouring sounds. For instance, the first consonant in the English word queen [kwi:n] is likely to be produced with rounded lips because it is followed immediately by a lip-rounded sound.

Cochlea: The organ of hearing. A spiral structure in the inner ear where mechanical vibrations are converted to nerve impulses.

Coda: A syllable constituent consisting of any consonant sounds following the syllable nucleus.

Complex periodic tone: A sound, such as a vowel sound, whose waveform can be analysed as the sum of two or more sine waves.

Compression: The rise in air pressure in an enclosed space caused by a decrease in the size of the space without outflow of air.

Continuum: A series of synthetic speech tokens used as stimuli in a speech perception experiment. Each member of the continuum is acoustically identical to the others except in the value of the particular acoustic feature under investigation.

Consonant: Sounds made with a relatively close constriction or complete closure in the vocal tract and which occur singly or in clusters at the edges of syllables.

Context-sensitive voicing: A phenomenon where the voicing of consonant sounds is determined by the context in which they appear. For example, young children often go through a stage in the development of their speech when all obstruent consonants are always voiced if they are immediately followed by a vowel and are always voiceless in other contexts.

Contour tone: A lexical tone which changes in pitch.

Contrast: The situation where a phonetic difference is capable of signalling a difference between words in a particular language. So for example, vowel nasalisation or lack of it in French can change the identity of a word, as can be seen with the pair of words mot /mo/ "word" and mon /mo~/ "my". So there is a contrast between oral and nasalised vowels in French. English, while it has oral and nasalised vowels, never uses the difference to signal the difference between words.

Creaky voice: A type of phonation in which the vocal folds vibrate at a low frequency (and usually somewhat irregularly) with a very low rate of airflow through the glottis.

Cricoid cartilage: A ring-shaped cartilage at the top of the windpipe. It is attached to the thyroid cartilage; the arytenoid cartilages sit on its upper surface at the rear.

Cue redundancy: The presence of more acoustic cues than are logically necessary to signal a perceptual distinction between speech sounds.

CV skeleton: A representation of the structure of a word or phrase in terms of the sequence of consonant and vowel sounds it contains. C is used to represent consonants and V to represent vowels. For instance, CVCV is the CV skeleton for English words such as below, city, data.

Defective vowel system: A type of vowel system, found in a small number of languages, which does not conform to the Vowel Dispersion Principle, either because it lacks open vowels or because, for mid and high vowels, there is an asymmetry of front and back vowels.

Degree of stricture: The narrowness of the space between two articulators during the production of a sound.

Dental: The name of a place of articulation. The active articulator is the tip or blade of the tongue. The passive articulator is the upper front teeth. [T D ] are examples of dental sounds.

Devoiced: Of a sound normally voiced, produced without vocal fold vibration for part or all of its duration.

Diacritic: A small mark placed near or attached to a phonetic symbol which is used to modify the usual meaning of the symbol or to supply further phonetic detail. For instance, [mß] represents a voiceless bilabial nasal whereas the symbol alone without the diacritic represents a voiced bilabial nasal.

Diphthong: A vowel which changes quality within a single syllable. An example of a diphthong in English is [aI], in such words as fine, time, sight.

Discrimination curve: A graph showing how well human listeners can distinguish between adjacent stimuli on an acoustic continuum.

Distribution: The environments in which a speech sound may occur in a particular language.

Double articulation: An articulation in which there are two simultaneous constrictions of the vocal tract. The two constrictions are of equal narrowness. [w] is an example of a double articulation.

Eardrum: A membrane stretched across the auditory canal and dividing the outer ear from the middle ear. The eardrum converts pressure variation into mechanical movement.

Egressive: Of an airstream mechanism, one which pushes air out of the vocal tract.

Electropalatography: An instrumental technique for investigating the pattern of contact of the tongue with the roof of the mouth during speech sounds. Tongue contact is recorded by electrodes embedded in an artificial palate worn by the speaker.

Elision: The omission of a sound. For example, the voiceless alveolar plosive phoneme may be elided in a phrase like last month, giving the pronunciation /lA:s mVnT/ rather than /lA:st mVnT/.

Ejective: A sound produced with an egressive glottalic airstream mechanism.

Ending: Another term for suffix. Sounds (or letters in the written form) added to the end of a word to indicate verb tense, the plural of nouns and the like. For example, the regular plural ending for English nouns is one of /s z Iz/, the choice depending on the last sound of the noun concerned.

Environment: The environment of a sound is the preceding and following sound or sounds. Statements of environments may also include the symbol #, which means a word boundary. For example, in a word like bring [b£IN], the environment of [£] is [b] __ [I] and that of [N] is [I] __ #.

Excitation: See Input.

Feature: See phonological feature.

Fibrescope: A flexible bundle of light-transmitting fibres used to collect an image from inaccessible areas inside the human body.

Fixed stress language: A language where the position of the primary stress is the same for the vast majority of words. For example, Polish is a fixed stress language because nearly all words have primary stress on the penultimate syllable.

Flap: A consonant produced by making the active articulator strike the passive articulator in passing. [±] is an example of a flap

Formant frequency: The frequency at which a peak in energy occurs in the spectrum of a speech sound.

Formant: A peak in the spectrum of a speech sound such as a vowel.

Fortis: Produced with increased muscular tension. Fortis speech sounds are normally voiceless.

Free stress: the same as variable stress.

Frequency: The rate of repetition of a cycle of vibration. Frequency is measured in Hertz (Hz). 1 Hz is one cycle per second, so for example if a periodic waveform repeats 100 times in a second, its frequency is 100 Hz.

Fricative: A consonant sound produced with a narrow constriction of the vocal tract which causes the airstream to become turbulent, resulting in audible friction noise. [s Z G] are examples of fricatives,

Frictionless continuant: an older term for approximant.

Front (of tongue): The part of the tongue which lies below the hard palate when the tongue is at rest.

Glide: an older term for approximant.

Glottal: The name of a place of articulation. The articulators are the vocal folds. [? h] are examples of glottal sounds.

Glottal Stop: The sound symbolised [?]. It is produced by closing the vocal folds tightly, blocking the airstream from the lungs.

Glottalic: The name of an airstream mechanism in which the closed vocal folds inititate the airflow. Ejective consonants are produced with an egressive glottalic airstream and implosives with an ingressive one.

Glottis: The space between the vocal folds.

Heavy syllable: A syllable which contains a long vowel or diphthong, or alternatively a short vowel followed by more than one consonant.

Height (of vowels): An auditory property of vowels, corresponding with the degree of raising of the highest point of the tongue during the production of a vowel.

Homophone: One of a pair (or larger set) of words which sound exactly the same when spoken, but which mean different things. For example, the words write, right, rite and wright are homophones in English, all being pronounced [raIt].

Implosive: A sound produced with an ingressive glottalic airstream mechanism.

Impressionistic transcription: A transcription of speech which represents its superficial auditory effect, but is not made in accordance with a stable and economical system of symbols worked out to suit the phonological structure of the language involved.

Infrasound: Low frequency vibration below the lower frequency limits of normal human hearing.

Ingressive: Of an airstream, one which pulls air into the vocal tract.

Initiator: The part of the vocal tract which moves in order to create a rise or fall in air pressure, resulting in flow out of or into the vocal tract. For instance, in the pulmonic airstream mechanism the initiator is the walls of the lungs.

Input: The energy introduced into a resonating system. An alternative term is “excitation”.
The input to the vocal tract is essentially of two kinds: (1) periodic energy produced by the vibration of the vocal folds (2) aperiodic energy produced by air turbulence caused by a narrow constriction or complete closure between two articulators. Some speech sounds, voiced fricatives especially, are produced with a combination of these two sorts of input.

International Phonetic Alphabet: A set of internationally agreed symbols used for representing speech sounds.

IPA: The International Phonetic Association or The International Phonetic Alphabet.

Intonational phrase: A group of words accompanied by a complete well-formed intonation pattern.

Key: An intonational feature which affects the pitch characteristics of a whole intonational phrase. If an intonational phrase is produced with high key, then all of the pitch values are higher. Similarly, low key makes all pitch values in the phrase lower.

Labelling curve: A graph showing the results of a labelling experiment. The horizontal axis shows the points in the acoustic continuum under investigation. The vertical axis shows the percentage responses for one of the two response labels for the experiment.

Labelling experiment: A speech perception experiment where large numbers of synthetic speech tokens are presented to human subjects. The subjects’ task is to respond to each token with one of two labels. For example, the subjects might be asked whether they hear each token as the word coat or as the word goat. The stimuli for the experiment are taken from an acoustic continuum of stimuli, but are presented in random order.

Labialisation: A secondary articulation involving the rounding of the lips.

Labial-palatal: The name of a double articulation with simultaneous articulations at the lips and at the hard palate. [H] is an example of a labial-palatal sound.

Labial-velar: The name of a double articulation with simultaneous articulations at the lips and at the velum. [w] is an example of a labial-velar sound.

Labiodental: The name of a place of articulation. The active articulator is the lower lip. The passive articulator is the upper front teeth. [f v] are examples of labiodental sounds.

Laminar flow: A characteristic of flow in a fluid such as air or water where the particles which make up the fluid move in parallel paths and there are few if any collisions between the particles. Laminar airflow does not create any sound.

Laryngograph: An electronic device which records vocal fold vibration by means of two electrodes placed externally on a speaker’s neck. A small electric current is passed through the neck and the laryngograph measures the changing resistance of the neck to the passage of the current. When the vocal folds are in contact, the resistance is lower than when they are apart.

Larynx: A structure made of cartilage and connective tissue at the lower end of the vocal tract and above the windpipe, containing the vocal folds.

Lateral: Of an approximant or fricative, produced with a complete closure on the midline of the vocal tract, but with one or both sides of the tongue lowered and not contacting the side teeth or gums, so that the air escapes over the sides of the tongue. [l K] are examples of lateral sounds.

Lenis: Produced with reduced muscular tension. Lenis speech sounds are usually voiced.

Lenition: A phonological process involving the change from a stronger sound to a weaker one, where stronger sounds are defined as having a more radical obstruction to airflow than weaker ones. For example, the change from a plosive to a fricative in certain environments is lenition and so is the change from a fricative to an approximant. In addition, voiceless sounds are stronger than voiced ones.

Lexical tone: The use of a small number of contrasting pitch patterns to distinguish words from one another.

Light syllable: A syllable which contains a short vowel followed by a maximum of one consonant.

Location (of vowels): The part of the tongue (front, centre, or back) which is raised highest in the oral cavity for the production of a vowel sound.

Logographic writing system: A writing system, such as that for Chinese, where the symbols used represent whole words, rather than the sounds or syllables which make up the word.

Long vowel: A vowel of relatively long duration when compared to a vowel of similar or identical quality in the same vowel system.

Loudness: The subjective impression of the magnitude of a sound. Loudness is connected with the amplitude of the waveform of the sound.

McGurk effect: A perceptual effect demonstrating that visual cues influence speech perception. A video of the speaker’s face is overdubbed with the soundtrack of an utterance different from the one which the viewer is seeing. The visual and auditory cues may be integrated by the hearer and the resulting perception can differ from both of the speaker’s utterances.

Magnetic resonance imaging: A non-hazardous technique for producing images of the interior of the body. The technique involves applying a very strong magnetic field to the body, followed by a radio-frequency pulse specific to hydrogen.

Manner of articulation: The way in which the articulators interfere with and direct the airstream for the purposes of producing speech sounds. Manner of articulation is a complex of features such as degree of stricture, speed of articulator movement, soft palate position and the like.

Meatus: another name for the auditory canal.

Median: Of a fricative or approximant sound, articulated in such a way that the air escapes down the midline of the vocal tract.

Minimal pair: A pair of words which differ in only one phoneme. An example from French: peau /po/ "skin" and beau /bo/ "beautiful".

Modal voice: A phonation type in which the vocal folds snap shut rapidly and peel apart relatively slowly. Most speech is produced with modal voice.

Monophthong: A vowel sound which does not change in quality.

Monosyllable: A word consisting of a single syllable, such as do and snap in English.

Nasal (stop): A consonant sound produced with a complete closure in the mouth but without velic closure so that the airstream escapes only through the nasal cavity. [m J N] are examples of nasals.

Nasal cavity: The large cavity above the roof of the mouth, connected to the upper part of the pharynx at the rear and having the nostrils at the front.

Nasalised vowel: A vowel sound produced without velic closure so that air escapes simultaneously through the oral cavity and the nasal cavity.

Nuclear tone: One of a small number of pitch configurations associated with the nucleus and any following syllables in the intonational phrase.

Nucleus: (1) The syllable which bears the last accent in an intonational phrase. (2) The only obligatory component of a syllable.

Neutralisation: The suspension, in certain environments, of a phonetic contrast normally found in a language. For example, voicing is contrastive for obstruent consonants in German, except at the end of words, where only voiceless consonants are permitted.

Non-pulmonic: Of airstreams mechanisms, not involving the lungs as an initiator. The two non-pulmonic airstream mechanisms used for speech sounds are glottalic and velaric.

Obstruent: A sound which is produced with a constriction narrow enough to cause an appreciable rise in air pressure inside the vocal tract. Plosives, affricates and fricatives are all obstruents.

Octave: An interval between two musical notes in a scale. If the frequency of any note is doubled, the result is the same note, but one octave higher.

Onset: A syllable constituent consisting of any consonant sounds preceding the syllable nucleus.

Oral: A sound produced with velic closure to prevent nasal escape of air, so that the airstream escapes through the oral cavity alone.

Oral cavity: The mouth. The cavity bounded by the lips at the front and joined to the pharynx at the rear.

Oral vowel: A vowel sound where all of the air escapes via the oral cavity and where there is no nasal airflow.

Ossicles: The three small bones of the middle ear which act as a linkage between the eardum and the oval window.

Oval window: An opening into the cochlea, covered by a membrane, to which mechanical movement is transmitted from the eardrum via the ossicles.

Palatal: The name of a place of articulation. The active articulator is the front of the tongue. The passive articulator is the hard palate. [j J] are examples of palatal sounds.

Palatalisation: A secondary articulation in which the front of the tongue is raised towards the hard palate.

Palatogram: A record of the pattern of contact between the tongue and the roof of the mouth during the production of a speech sound.

Parametric diagram: A diagram showing the estimated movements or activity of various parts of the vocal tract such as the soft palate and the vocal folds.

Paralinguistic feature: a feature of speech, such as loudness or voice quality, used to convey speaker attitude rather than linguistic meaning.

Passive articulator: The stationary articulator involved in forming a constriction in the vocal tract. For instance, the hard palate is the passive articulator for both palatal and retroflex sounds.

Periodic: Of a waveform, regularly repeating in time.

Pinna: the outer, visible part of the ear.

Pharyngeal: The name of a place of articulation. The active articulator is the root of the tongue. The passive articulator is the rear wall of the pharynx. [‘ ] are examples of pharyngeal sounds.

Pharyngealisation: A secondary articulation in which the root of the tongue is retracted and approaches the rear wall of the pharynx.

Pharynx: The part of the vocal tract immediately above the larynx.

Phonation: The generation of voice in the larynx, by vibration of the vocal folds.

Phoneme: A set of speech sounds which form a basic contrastive unit in a language. For example in English, the set which contains the sounds [l 5 l~ 5~ lß], amongst others, is the /l/ phoneme. The members (or allophones) do not contrast with one another in the language in question.

Phonetic Symbol: A symbol representing a speech sound.

Phonetic Transcription: The representation of speech using phonetic symbols.

Phonological feature: One of a small set of labels used to specify an aspect of the articulation (or of the acoustic properties) of a speech sound or a set of speech sounds. For example, the phonological feature [anterior] is used to distinguish those sounds produced on or in front of the alveolar ridge from those sounds produced further back in the vocal tract.

Phonological process: A widespread phonological phenomenon such as assimilation, elision or lenition.

Phonotactics: The patterning of permissible phoneme sequences in syllables.

Pitch: The perceptual attribute of a sound which enables the hearer to locate the sound on a scale from high to low. The physical correlate of pitch is the frequency of the sound.

Place of articulation: The point within the vocal tract where a constriction is formed to produce a consonant sound. The place of articulation is defined by the active and passive articulators involved.

Plosive: A consonant sound produced with a complete closure between two articulators and with velic closure preventing air escaping via the nasal cavity. The articulators part rapidly allowing rapid release of the compressed air without any accompanying friction noise. [p d c q] are examples of plosive sounds.

Postalveolar: The name of a place of articulation. The active articulator is the tip or blade of the tongue. The passive articulator is the rear of the alveolar ridge. [£ S Z] are examples of postalveolar sounds.

Pre-fortis clipping: The reduction in duration of sonorant sounds when followed in the same syllable by a fortis consonant. For example, the vowel in the English word seat [si:t] is clipped, whereas that in seed [si:d] is not.

Pressure: The molecules which make up a gas such as air are constantly moving and colliding with the surface of objects which contain the gas. The force created by the sum of these collisions is the pressure of the gas. Pressure is measured in force per unit area.

Primary articulation: The narrowest constriction in the vocal tract during the production of a speech sound.

Primary stress: See Stress.

Prosodic: the same as suprasegmental

Pulmonic: The name of an airstream mechanism in which the lungs initiate the airflow. The majority of sounds of human speech are produced with a pulmonic egressive airstream.

Pure tone: The sound associated with a sine wave.

Rarefaction: The fall in air pressure in an enclosed space caused by an increase in the size of the space without inflow of air.

Register tone: A lexical tone with a level pitch contour.

Resonant frequency: The frequency at which an acoustic system vibrates when excited by input energy.

Retracted: Produced slightly further back in the vocal tract. For instance, the first consonant in the English word trip is a retracted alveolar and is produced at the back of the alveolar ridge.

Retroflex: The name of a place of articulation. The active articulator is the tip of the tongue. The passive articulator is the hard palate. [µ † ´] are examples of retroflex sounds.

Rhyme: A syllable constituent consisting of the syllable nucleus plus the coda.

Roll: Another term for trill.

Root (of tongue): The very back part of the tongue which faces the rear wall of the pharynx.

Rounded: Of a vowel, produced with rounded lips. [y u o O] are examples of rounded vowels.

Rule: A statement of a phonological phenomenon in terms of the input (the sounds affected), the output (he changes made), and the context in which the change occurs. An example is: [-son] > [-voi] / __ [-voi]. This means: any obstruent (the input) becomes voiceless (the output) before another voiceless sound (the context).

Sampling rate: The frequency with samples are taken from a waveform for the purposes of digitising speech. For example, a sampling rate of 10kHz means that each second of the waveform is represented by 10,000 equally spaced samples.

Secondary articulation: A constriction of the vocal tract which takes place at the same time as a narrower constriction elsewhere. [5] is an example of a sound where the secondary articulation is formed by the tongue back being raised towards the soft palate while at the same the tongue tip makes the primary articulation (a complete closure on the alveolar ridge).

Secondary stress: See Stress.

Segment: Another term for speech sound.

Semivowel: A type of approximant sound, like [w] or [j], whose articulation is very similar to that of a vowel.

Short vowel: A vowel of relatively short duration when compared to a vowel of similar or identical quality in the same vowel system.

Sine wave: A waveform with a simple shape and a single constant frequency and constant amplitude.

Soft palate: The rear part of the roof of the mouth.

Sonorant: An articulation where the constriction is not so narrow, or is not of sufficient duration, as to cause an appreciable rise in air pressure inside the vocal tract. Vowels, nasals, approximants, taps, flaps and trills are all sonorants.

Spectrum: A visual display of the relative amplitudes of the different frequency components of a sound such as a vowel.

Stop: A consonant sound which involves a complete closure in the oral cavity. Plosives, affricates and nasals are all stops.

Stress: The relative prominence of syllables. In many languages one (or more) syllables in a word are produced louder and longer than others. These syllables are said to be stressed. Examples from English: butter, teaching (first syllable stressed) and resign, unsure (second syllable stressed). In many languages there is more than one degree of stress. So, for example, in the English word international there is a primary stress on the third syllable and a secondary stress on the first syllable: [%Int@"n{Sn@l].

Stress-timed language: A language whose rhythm shows perceptually equal time intervals between stressed syllables.

Stroboscope: A device which can take a series of photographs very rapidly. Adjustment of the timing of the photographs can appear to freeze, or slow down, very rapid periodic motion.

Suprasegmental: A name for features such as stress, lexical tone and intonation, which affect more than one segment.

Syllabary: A system of writing where the symbols used represent whole syllables rather than the individual consonants and vowels which make up the syllable.

Syllabic: Of a speech sound, capable of forming the core of a syllable. In most languages vowels are the only syllabic sounds, but some consonants, mainly sonorants, are also used as syllabic sounds in some languages.

Syllable: A phonological structure composed of speech sounds. Words are made up of syllables. The syllable is the domain of association for such phenomena as stress and lexical tone.

Syllable-timed language: A language whose rhythm is based on perceptually equal duration of syllables.

Synthetic speech: An electronic simulation of human speech.

Tap: A consonant sounds produced by making the active articulator strike the passive articulator for a very brief duration. [4] is an example of a tap.

Thyroid cartilage: The largest cartilage of the larynx. It is attached to the cricoid cartilage below and is supported by muscles attached to the bones of the skull. The front ends of the focal folds are attached to its inner surface.

Tip (of tongue): The extreme front end of the tongue.

Tone: See lexical tone.

Toneme: A group of pitch configurations which are functionally equivalent in a particular lexical tone language.

Trill: A consonant sound where the active articulator vibrates rapidly striking the passive articulator repeatedly. [r ³] are examples of trills.

Turbulent flow: A characteristic of flow in a fluid such as air or water where the particles which make up the fluid move in a chaotic, unpredictable fashion. The particles collide with each other and the energy created by these collisions is heard as noise.

Tympanic membrane: Another name for the eardrum.

Ultrasound: High frequency vibration above the upper frequency limit of normal human hearing.

Unrounded: Of a vowel, produced without rounding of the lips. [i a M] are examples of unrounded vowels.

Uvula: The fleshy protuberance which hangs from the end of the soft palate.

Uvular: The name of a place of articulation. The active articulator is the back of the tongue. The passive articulator is the uvula. [q Œ ª] are examples of uvular sounds.

Variable stress language: A language where the primary stress is not fixed to a particular position in a word.

Velar: The name of a place of articulation. The active articulator is the back of the tongue. The passive articulator is the soft palate. [k g N] are examples of velar sounds.

Velaric: The name of an airstream mechanism in which the airflow is intitiated by a closure of the back of the tongue on the velum. Clicks are produced with a velaric ingressive airstream.

Velarisation: A secondary articulation in which the back of the tongue is raised towards the velum.

Velic closure: The closure formed by raising the soft palate to contact the rear wall of the pharynx. Oral sounds are produced with velic closure, which prevents air escaping via the nasal cavity.

Velopharyngeal: The same as velic.

Velum: Another name for the soft palate.

Vocal cords: An older term for the vocal folds.

Vocal folds: Two folds of tissue with embedded muscle and ligaments found inside the larynx. They are attached at the back to the arytenoid cartilages and at the front to the inner surface of the thyroid cartilage. Their vibration is the source of the periodic energy for human speech sounds.

Vocal tract: The oral cavity, nasal cavity, pharynx and larynx.

Voice Onset Time: The time lapse, measured in milliseconds, between the release of a plosive sound and the onset of voicing for the following sound. Voice onset time is an important perceptual cue for voicing of plosives.

VOT: The abbreviation for Voice Onset Time

Vowel Dispersion Principle: The tendency for vowel systems to consist of qualities which are widely and evenly dispersed in perceptual space.

Vowel system: The set of contrastive vowel qualities found in a particular language.

Vowel: A sound produced without a close obstruction in the vocal tract and which forms the centre of a syllable.

Wav file: One common format for storing sounds as computer files.

Waveform: A visual representation of the variation of air pressure caused by a sound. The horizontal axis represents time and the vertical axis represents pressure variation above and below atmospheric pressure.