Speech Science

W. BarryInstitut für Phonetik, Universität des Saarlandes

IPUS

Version Okt. 2007

Term Programme 1

Wk 1 : • What is Speech Science - scientific goals? Übung 1

Wk 2 : • Capturing and representing Speech Übung 2

Wk 3 : • Speech production I – Breathing Übung 3

Wk 4 : • Speech production II – Speech organs and articulation; Übung 4

Wk 5 : • Speech production III – Speech motor control 1; Übung 5

Wk 6 : • Speech production IV – Speech motor control 2; Übung 6

Wk 7 : • Acoustic structure of speech I – Source-Filter Übung 7

Term Programme 2

Wk 8 : • Acoustic structure of speech II – Vowels Übung 8

Wk 9 : • Acoustic structure of speech III – Consonants Übung 9

Wk 10: • Variable acoustics – constant perception Übung 10

Wk 11: • What do we perceive? Sounds/syllables/words? Übung 11

Wk 12: • What happens in fluent speech? – Articulation and acoustics; Übung12

Wk 13: • What do we produce when we speak? Sounds/syllables/words?; (distribute trial exam) Übung 13: Discussion of trial exam  

Term Programme 3

Wk 14: • Discussion of practice examWk 15: • Final examCoursebooks:R. D. Kent (1997). The Speech Sciences. San Diego/London: Singular

Publishing Group, Inc.G.J. Borden, K.S. Harris & L.J. Raphael (1994). Speech Science Primer.

Physiology, Acoustics and Perception of Speech. (3rd edition). Baltimore: Williams & Wilkins.

B. Pompino-Marschall (2003). Einführung in die Phonetik. (2nd edition) Berlin/New York: Walter de Gruyter

H. Reetz (1999). Artikulatorische und akustische Phonetik. Wissen-schaftlicher Verlag Trier (WVT).

What is Speech Science?

Topics• Scientific goals

• Areas of Speech Science-------------------• "Homework": a) Kent, Chap. 1, pp. 1-20 (K)

b) Borden, Harris & Raphael, Chap. 2, pp.14-23 (BHR)

Deutsch: c) Pompino-Marschall, Teil I, S. 1-10; Teil II, S. 13-16 (P-M)

Scientific goals

• Science: Seeks to explain the “Hows?” of the world

• What are the “Hows?” of speech?

• For any question “How?” there has to be a “What?”

• So … what is speech?The systematic movement of our articulators?The sound patterns we perceive?The sound waves that travel from speaker to hearer?Anything else?

What is speech?

• All of the things mentioned ……. but more!

• We really need a “communication framework” for speech to actually take place

• The articulatory movements The acoustic pressure patterns The sound patterns that we perceive HAVE TO BE RELATED TO A MESSAGE

• ……… so what do we mean by “message”?

The “message” of speech?• ….. is the information the speaker conveys to the listener

Which is?• Mostly, the semantic content of the utterance

(though this can be metaphoric or otherwise indirect)

• Also, the speaker’s attitude to the content ….. and to the person(s) being talked to

• But speech also reflects things about the speaker (indexical information: sex, age, health, mood ……)

• So the relationship between message and sound patterns is much more than how /i a u/ and /p t k/ are produced.

Speech as a meta-message?• Our definition of “message” can be problematical for speech research:

• Speech research is often associated with unnatural utterances …(something our definition rejects as “genuine speech”?)Words set in carrier sentencesWord lists containing target soundsRepeated phrases……. etc.

However…..• Within the framework of the research question they DO convey

information to the listener (= to the investigator)…. As a meta-message = a message about the linguistic form

So, within a particular theoretical question it can be valid material.

• But such speech can never be considered “natural speech”

So, do we now know WHAT speech is?• A message encoded in language and expressed phonetically

(i.e. through the medium of sound) …..

• ….. which means that a speaker is active, an acoustic signal is produced…..

• ….. and it is assumed that the speaker is talking to someone. I.e., a hearer receives and processes the signal (decodes the message)

This “speech chain” defines the broad area within which Speech Science asks its questions.

Speech Chain

neuralprocesses

neuro-muscul.process

Articulation

Acoustics

Hearing

system

Stimulustransform

neuralprocesses

Observation domains

Observation domains within the speech chain (adapted from P-M. p.14)

Measure-ment

Speech signal Speech signaltimeas a function of

C

NS

CN

S

Speech Chain IIFrom Denes & Pinson, 1993, p. 5

Observation domains I• Neural processes (production and perception) –

increasingly of interest (psychology & medicine)EEG (Electroencephalography) and MEG (Magnetoencephalography) MRI (Magnetic Resonance Imaging)

• Global information about neural activity:EEG and MEG provide high temporal resolution of

activity in small areas of the brain.MRI shows activity in all areas of the brain but with low temporal resolution.

• Nothing is clear from one observation (noisy signals). Patterns emerge from the average of many repetitions.

Observation domains II• Neuro-muscular processes (production) EMG (Electromyography)

Observation domains III• Articulation (Production) – Traditional observation domain in

Phonetics.

Larynx Trachea

Jaw

Hard palate

Soft palate

Tongue

Nasal cavity

Pharynx

Epiglottis

Observation domains IV• Acoustic Signal – Increasingly central to speech research from

1945 onwards.

• It has a central positionbetween speaker and hearer; it is the product of articulation and the input to the perception process.

• Different representationsgive us information about the distribution ofacoustic energy in timeor in frequency.

a)

b)

Observation domains V• Auditory system (the physiological and neurological foundation

of perception)

The peripheral auditory system (ear)

Eardrum &Malleus

Middle earInner ear

Outer ear

Ear canal

StapesIncus

Semi-circular canalsbalance nerve auditory nerve

Ovalwindow

Roundwindow

Endolymphduct

Cochlear

Scala vestibuli

Scala tympani

Observation domains VI• Stimulus transformation (psycho-acoustics, psycho-phonetics,

speech perception)

• What are the acoustic properties that keep vowels and consonants, monophthongs and diphthongs, stops and fricatives, voiced and voiceless consonants apart?

• The “same sound” is acoustically different when it is produced by different speakers – very different if the speakers are men vs. women vs. children. Why do they sound the same?

• The “same sound” is acoustically different when it is produced in different contexts.

Summing up……• Different observation domains give us different perspectives on

what people do to communicate.

• Examining the phonetic events in relation to the message gives us:a) a lot of knowledge about the structure of speechb) insight into how the properties of speech affect the

message

• This serves many purpose: -The formulation of theories of speech (production and perception)

-The development of pronunciation-teaching methods and therapies for the speech impaired -Applications in speech and language technology