Speech Acoustics and Phonetics: Selected Writings (Text, Speech and Language Technology)

333 Pages·2005·12.4 MB·English

by  Gunnar Fant

SPEECHACOUSTICSANDPHONETICS
Text,SpeechandLanguageTechnology
VOLUME24
SeriesEditors
NancyIde,VassarCollege,NewYork
JeanVe´ronis,Universite´ deProvenceandCNRS,France
EditorialBoard
HaraldBaayen,MaxPlanckInstituteforPsycholinguistics,TheNetherlands
KennethW.Church,AT&TBellLabs,NewJersey,USA
JudithKlavans,ColumbiaUniversity,NewYork,USA
DavidT.Barnard,UniversityofRegina,Canada
DanTufis,RomanianAcademyofSciences,Romania
JoaquimLlisterri,UniversitatAutonomadeBarcelona,Spain
StigJohansson,UniversityofOslo,Norway
JosephMariani,LIMSI-CNRS,France
Thetitlespublishedinthisseriesarelistedattheendofthisvolume.
Speech Acoustics
and Phonetics
by
GUNNARFANT
DepartmentofSpeech,MusicandHearing,
RoyalInstituteofTechnology,
Stockholm,Sweden
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CONTENTS
Foreword vii
Preface ix
Introduction xi
Listofselectedarticles xiii
1. Speechresearchoverview 1
2. Speechproductionandsynthesis 15
3. Thevoicesource 93
4. Speechanalysisandfeatures 143
5. Speechperception 199
6. Prosody 221
Publicationlist1945–2004 301
Referencecategories 319
v
FOREWORD
byLouisC.W.Pols
UniversityofAmsterdam
Since almost 60 years Gunnar Fant has actively contributed to the field of Speech
AcousticsandPhonetics.Almosteveryspeechscientistintheworldknowshimbe-
causeheisstillafrequentvisitorofconferencesandworkshopsallovertheworld.
Theymayalsoknowaboutsomeofhiswork,butonlyfewhaveaproperknowledge
aboutthedetailsandthebreadthofhispioneeringandstillongoingresearch.This
is partly related to the fact that in the early days many of his contributions were
onlypublishedintheQuarterlyProgressandStatusReports(QPSR)oftheSpeech
Transmission Laboratory (STL) of the Speech Communication and Music Acous-
ticsdepartment,latercalledthedepartmentofSpeech,MusicandHearing(TMH)
of the Stockholm Royal Institute of Technology (KTH). Several other important
publications only appeared in various conference proceedings or in not easily ac-
cessible journals. It is most fortunate that Gunnar Fant has taken up the challenge
toproducethisbookofSelectedWritings.Itishisownuniqueselectionanditonly
containspublicationsfromhisownhandwithorwithoutcolleagueco-authors.Via
the Introductions per section he guides us himself through the multitude of topics
andexplainsthehistoricaldevelopmentsandthevariousconnections.Itmakeses-
pecially those older publications accessible that otherwise would have been very
hard to find. I suggested to him to extend as much as possible the introductions to
each of the six main chapters (Speech research overview; Speech production and
synthesis;Thevoicesource;Speechanalysisandfeatures;Speechperception;and
Prosody).This,inmyopinionhassubstantiallycontributedtothereadabilityofthe
19individualcontributions.Itwasdifficultforhimtolimithimselftothese19papers
only,asonecanimaginefromhisfulllistofpublicationswithover260oldandnew
titles,thathepresentsbothchronologicallyaswellastopic-wise.Neverthelessyou
havethisgoldminenowinfrontofyouandIhopeandexpectthatthiswillbejoyful
andinformativereading.
GunnarFanthasbeenawardedmanytimes,mostrecentlyinJune2004withthe
new IEEE James L. Flanagan Speech and Audio Processing Award, together with
anotherspeechgiantKenStevens,fortheir“fundamentalcontributionstothetheory
and practice of acoustic phonetics and speech perception”. Still I believe that the
mostvaluablecontributionofascientisttothescientificandworldcommunityare
hisproductsinwriting,especiallywhentheyaremadeaccessibleinsuchasplendid
formasinthisbook.
His pioneering book on the “Acoustic theory of speech production” published
in 1960 by Mouton, is of course a classic that is for instance still invaluable in
articulatory synthesis. However, many other topics, like the formant banana, the
Jakobsen-Fant-Halledistinctivefeatures,theLFsourcemodel,theOVEsynthesiser,
vii
viii Foreword
theinvariance-variabilitydispute,syllableprominenceandthespeechcode,getmuch
attentionandarepresentedintheproperperspectiveinthepresentbook.Thefinal
sectionisaboutProsody,thetopicthatkeepshimmostbusythesedays.Heworks
on it together with Anita Kruckenberg and Johan Liljencrants, and it concerns not
justtheprosodyofspokenSwedishbutalsothatofpoetry.
PREFACE
Thisisacollectionofarticlesspanninghalfacenturyofspeechresearch.Itstarted
attheEricssonTelephoneCompanyinStockholm,1946–1949.Thefollowingtwo
years were spent at MIT. In 1951 a small research group was established at the
KTH in Stockholm. This unit, the Speech Transmission Laboratory, became the
foundation for our present department of Speech, Music and Hearing. An early
expansionwaspromotedbyUSgrantsinthe1960’s.Researchinspeechacoustics,
phonetics,hearingandhandicapaidsdominatedtheactivitiesupto1990,afterwhich
moreappliedprojectsinspeechtechnologygaineddominanceatthedepartment.
MuchofourworkwaspublishedinourSpeechTransmissionLaboratoryQuar-
terlyProgressandStatusReports(STL-QPSR).Ithadtheadvantageofreachinga
largeinternationalforumwithaminimumofdelay,butgavelesstimeforpublica-
tionsinestablishedjournals.Thepurposeofthepresentbookistomakeavailable
a collection of articles from various reports and publications, which contribute to
theknowledgefoundation.Itisnotastructuredtextbook,butitprovidesareference
materialforquiteawiderangeoftopicsinthefield.
ItiswithgreatgratitudethatIacknowledgethecontributionsfromallthosewho
havebeeninvolvedindevelopingourdepartmentanditsresearchandhaveservedas
co-workers.Theyaretoomanytobelistedhere,buttherearetwopersonsfromthe
earlydaysthatIwanttomention.MarianneRichter,myfirstemployee,participated
in language statistics and became our first finance officer. Si Felicetti started our
STL-QPSR in 1960 and promoted our international contacts. My present research
is carried out together with Anita Kruckenberg and Johan Liljencrants. They and
my many friends in the scientific community have contributed to the delight of
cooperation and scientific discoveries. Closest in research profile is Ken Stevens.
Hisbook,AcousticPhonetics,isofmonumentalvalueandprovidesdeeperinsights
inmattersofspeechproduction.
ValuablesuggestionsfortheplanningofthevolumeweregivenbyLouisPols.
ix
INTRODUCTION
As time goes by, a look ahead in science and technology gains by a spotlight on
earlier periods. Speech technology has provided important tools for applications
in man-machine communication systems and is growing rapidly. But there is a
risk that expansion will be limited by insufficient attention to the potentialities
of speech and language research. The symbiosis between technology and basic
research that has made possible the advance, now shows a tendency to turn into
polarization.Speechtechnologyishighlydependentonstatisticaltoolsandlargedata
bases,whilstphoneticstendstobecomefractionalisedbynarrowlydefinedproblems
or by abstract issues with small or no relevance for the overall code of spoken
language.
Thereisagreatneedforintegratedbasicknowledgeofspeechproduction,acous-
tics, perception and cognitive processes and of the encoding of linguistically de-
fined units in the speech wave and other parts of the overall speech chain. In sev-
eral articles I have attempted to coin the concept of these relations as the speech
code.Therelativesuccessofspeechsynthesishascreatedanillusionthatwehave
a profound insight in the speech code. This illusion becomes especially appar-
ent when operating in the reverse direction, that is, given a record of the speech
wave we attempt to decipher what was said. An example is spectrogram reading,
a difficult but rewarding exercise, which is mediated by knowledge about speech
production.
In quest of the speech code, we are faced with issues concerning invariance
and variability. However, the invariance issue ceases to present a problem if we
systematicallydeveloprulesforstructuringvariabilityofallkinds,notonlylanguage,
dialectalandcontextualvariationsbutalsovariationsspecifictospeaker,speaking
style and emotions. Much more effort is needed to develop the code and make it
availableforpracticalapplications,aswellasfortheadvanceofgeneralphonetics
andlinguistics.Itisonlywithaprofoundknowledgeofthespeechcodeandhuman
behaviourthatwecanrealizeultimategoalsofadvancedandreliablesystems.
The 19 selected articles span a period of almost 50 years. Some of the older
ones still maintain a pedagogical value, or they document unique studies of some
significance. I have arranged them in six chapters according to categories, which
havesomeinevitableoverlapofcontents.
They have been selected from my complete publication list, which has been
structuredinannualorderwithanumbertagforeachitemofaparticularyear.Ina
separatetabletheyhavebeensortedincategoriesconformingtothoseoftheselected
articlesandadditionalactivities.
Seven of the articles originate from our STL-QPSR laboratory reports, now the
TMH-QPSRofthedepartmentofSpeech,MusicandHearingofKTH.Theyhave
beendistributedin800copiesto50differentcountries.From2001theyareavailable
ontheInternetonly.
xi
xii Introduction
The first chapter contains a single article devoted to the development of pho-
neticsandspeechtechnologyinahistoricalperspective,viewedfrommypersonal
experiencesduringmorethanhalfacentury.
The topic of the second chapter is speech production and synthesis. It contains
five articles related to my Acoustic Theory of Speech Production (Fant, 1960),
earlier work at the Ericsson Telephone Company, and follow-up studies of vocal
tractconfigurationsandassociatedcircuittheory.Ourearlyformantbasedsynthesis
systemisdescribed,andalsoanovelsynthesizerintendedforarticulatorycoding.
Chapter3isdevotedtothevoicesource.Threemajorarticlesareincluded.They
dealwithpropertiesoftheLF-model,glottalsource-vocaltractinteraction,inverse
filteringandapplicationsinspeechsynthesis.Frequencydomainaspectsaregiven
specialattention.
Chapter4containsfourarticlesdevotedtoacousticphoneticdescriptiveanalysis
ofspeechwithinaspectrographicframe,aswellasinterpretationswithreferenceto
distinctivefeatureanalysisandtheconceptofthespeechcode.
Chapter 5 contains two articles, one on auditory modelling applied to vowel
perception,includingtheoryandexperimentsontwo-formantapproximations.The
second article addresses a problem in audiology, to predict intelligibility at a spe-
cifichearinglossfromapuretoneaudiograminrelationtothefrequency-intensity
distributionofspeechformants.
Duringthelast15yearsasubstantialpartofmyworkhasbeendevotedtoprosody
togetherwithAnitaKruckenberg.Thefirstarticleinchapter6reviewsourfindings
of quantal patterns in segmental timing, and the second is devoted to the acoustic
realization of meter and rhythm in poetry reading, The third article reports on the
greatindividualspreadinpausingwithinasentence,anddifferencesbetweenprose
readingandnewsreading.Thefortharticleprovidesacomprehensiveanddetailed
overviewofourworkonSwedishprosody,coveringtheacousticphoneticbasisof
syllabicstressandperceivedprominence,intonationpatternsandmodelsofspeech
synthesis. The descriptive frame has a foundation in voice source properties and
aerodynamics.
More detailed comments supplementing the brief presentation above are to be
foundintheintroductionstotheseparatechapters,withlistsofarticlesrecommended
foradditionalreading.