spoken language accent detection

30 Pages·2014·0.22 MB·English

SPOKEN LANGUAGE ACCENT
DETECTION
Probabilistic Accent Detection Using
Hidden Markov Models
Tre´ Calhoun
La Vesha Parker
Andrew Vaslas
Nicolas Vera
CornellUniversity
CONTENTS
Introduction iv
PART I HTKSOFTWARESUITE
1 InstallationofHTKSoftware 2
1.1 GeneralInstallationinformation 2
1.2 MacOSX 2
1.3 Windows 3
2 TrainingandTestingCorpusAcquisition 5
2.1 TheOnlineSpeech/CorporaArchiveandAnalysisResource(OSCAAR) 5
3 TrainingCorpuswithHTK 7
3.1 RecordorInputSoundFiles 7
3.2 LabelingtheSoundFiles 8
4 CodingtheData 9
4.1 MelFrequencyCepstralCoefficients 9
4.2 Obtaining.mfccFiles 9
4.2.1 ConfigurationFile 9
4.2.2 TheCreationoftargetlist.txt 10
4.3 CommandLineActions 10
5 SettingParametersfortheHiddenMarkovModel 11
5.1 WhatisaHiddenMarkovModel? 11
5.2 HMMsandAccentDetection 12
5.2.1 Overview 12
5.2.2 HMMDefinition 12
5.2.3 Training 14
5.3 CommandLineActions 14
6 DefiningYourTask 16
6.1 DefineYourGrammar 16
6.2 DefineYourDictionary 17
6.3 GeneratingtheNetwork 17
7 Recognition 18
7.1 Procedure 18
7.2 CommandLineActions 18
PART II ERRORHANDLING,SOFTWAREUSEDANDRESOURCES
A ErrorHandling 21
B SoftwareUsed 22
C References 24
References 25
iii
INTRODUCTION
Variousaccentsposeaproblemtoautomatedspeechrecognitionsoftware. Ifaccentscan
bemoreeasilydetected,differentspokenlanguagemodelscanbeappliedtospeechrecog-
nitionsoftwaretomakeforamorecorrectinterpretationofspokenlanguage.
In this tutorial, we describe our exploration of Cambridge University’s Hidden Markov
ModelToolkitasatooltouseforspokenaccentprediction. Weexploretheclassification
ofthepronunciationoftheword”security”asspokenbynativeEnglishandnativeSpanish
speakers.
Weprovideadditionaldataindata general/forthosewhowishtoexploreadditional
accentclassifications.
PART I
THE HIDDEN MARKOV MODEL
TOOLKIT SOFTWARE SUITE
CHAPTER 1
INSTALLATION OF HTK SOFTWARE
1.1 GeneralInstallationinformation
The website for HTK can be found here. The HTK developers require that you register
forausernameandpasswordthroughtheirsitebeforedownloadingtheirsoftware. After
registering, visit the downloads page and download the HTK source code (available as a
tarball). ItisalsousefultodownloadtheHTKBookasaPDF(availableonthedownloads
page, below the software). If you do not wish to download the book, you can view the
bookonlineafterregistering.
1.2 MacOSX
In order to install HTK for Mac OS X, you first need to make sure that you have Xcode
developertoolsandX11installed.
WhatfollowsaretheinstallationinstructionstakendirectlyfromtheREADMEintheroot
directory of the unziped htk/ directory, save a bit of formatting. We do not claim this
work,andrepeatithereonlyforconvenience.
1.2.0.1 Compiling&InstallingHTKunderUNIX/Linux,OSXorCygwin
Afterunpackingthesources,cdtothehtk/directory.
TherearenowtwowaystoinstallHTK,the”traditional”andthe”new”. UptonowHTK
hasalwaysinstalleditstoolsastheywerebuilt, andinstalledthemtoadirectorysuchas
”bin.linux”sothatbinariesfordifferentarchitecturescanbeinstalledinahomedirec-
torysay.Ifyouwanttoinstallinthisway,pleaseaddtheoption”--enable-trad-htk”
whenyourunconfigure.
The”new”methodinstallsbydefaultinto/usr/local/bin(equivalenttoaconfigure
optionof”--prefix=/usr/local”).
1. decidewhichoftheabovemethodsyouwishtouse
2. cdtohtk,thenrun./configure(withappropriateoptions,run”./configure
--help”ifunsure). Ifyoudon’twanttobuildtheprogramsinHLMToolsaddthe
–disable-hlmtoolsoption.
3. make all
4. make install
Running”make install”willinstallthem. Thisstepmayneedtobedoneasroot, if
youarenotinstallingtheminyourhomedirectory.
NotesforparticularUnixvariants:
Solaris:if”make”isn’tinstalledyoumayneedtoadd/opt/sfw/binand/usr/ccs/bin
to your path and run ”./configure MAKE=gmake” with any other options you re-
quire. Thenrun”gmake”insteadof”make”,alternativelyyoucancreateasymboliclink
called”make”somewhereityourpathto/opt/sfw/bin/gmake
1.3 Windows
Onceagain,whatfollowsaretheinstallationinstructionstakendirectlyfromtheREADME
intherootdirectoryoftheunzipedhtk/ directory, saveabitofformatting. Wedonot
claimthiswork,andrepeatithereonlyforconvenience.
1.3.0.2 Compiling&InstallingHTKunderWindows
Prerequisites:
HTKhasbeenverifiedtocompileusingMicrosoftVisualStudio.
Fortesting,youwillrequireaPerlinterpretersuchasActivePerl.
ProbabilisticAccentDetectionUsingHMMs. 3
ByCalhoun,Parker,Vaslas,andVera
4 INSTALLATIONOFHTKSOFTWARE
You will need a tool such as 7-zip or winzip (commercial) for unpacking the HTK
sourcecodearchive.
ItitishelpfulifyouhavesomefamiliaritywithusingtheDOScommandlineinter-
face,asyouwillneedtointeractwithitinordertocompile,installandrunHTK.
EnsurethatyourPATHcontains:
C:\Program Files\Microsoft Visual Studio .NET 2003\Vc7\bin
Orifyouareusingolderversions:
C:\Program Files\Microsoft Visual Studio\VC98\bin
Compilation:
1. UnpacktheHTKsourcesusing7-zip.
2. OpenaDOScommandwindow: ClickStart,selectRuntypecmdatthepromptand
clickOK.
3. cdintothedirectoryinwhichyouunpackedthesources.
4. cdintothehtk/directory. Type:
cd htk
5. Createadirectoryforthelibraryandtools. Type:
mkdir bin.win32
6. RunVCVARS32(itshouldbeinyourpath,seeprerequisitesabove)
7. BuildtheHTKLibrary,whichprovidesthecommonfunctionalityusedbytheHTK
Tools. Enterthefollowingcommands:
cd HTKLib
nmake /f htk_htklib_nt.mkf all
cd ..
8. BuildtheHTKTools
cd HTKTools
nmake /f htk_htktools_nt.mkf all
cd ..
cd HLMLib
nmake /f htk_hlmlib_nt.mkf all
cd ..
cd HLMTools
nmake /f htk_hlmtools_nt.mkf all
cd ..
Installation:
TheHTKtoolshavenowbeenbuiltandareinthebin.win32directory. Youshouldadd
this directory to your PATH, so that you can run them easily from the command line in
future.
CHAPTER 2
TRAINING AND TESTING CORPUS
ACQUISITION
Everyonehastherighttolife,libertyandsecurityofperson.
—UnitedNations’DeclarationofHumanRights[4]
2.1 TheOnlineSpeech/CorporaArchiveandAnalysisResource(OSCAAR)
Northwestern University’s Online Speech/Corpora Archive and Analysis Resource (OS-
CAAR) is a collection of speech recordings from speakers with different backgrounds,
assembledfromvariousdatasets.
To request access to the data available through OSCAAR, you can submit a request for
accesstotheOSCAARcollections. Inourexperience,requestsarehandledabout24–48
hoursafterbeingsent.
The dataset that we found most appropriate for our goal of accent detection and classifi-
cationistheALLSTARdatasetfromtheSpeechandCommunicationResearchGroupat
NorthwesternUniversity. Thedatasetismassive,andwefoundthatasubsetofsamplesfit
ourneedswell.
Partofthedatasetfeaturesrecordingoftalkersfromdifferentbackgroundssaying20sen-
tencespulledfromtheDeclarationofHumanRightsinEnglish. Forourproofofconcept,
ProbabilisticAccentDetectionUsingHMMs. 5
ByCalhoun,Parker,Vaslas,andVera
6 TRAININGANDTESTINGCORPUSACQUISITION
weusedasubsetofthatportionofspeakersreadingArticle3fromtheDHR:”Everyone
hastherighttolifelibertyandsecurityofperson.”Thatsubsetofthedatafeaturedtalkers
withthefollowingnativetongues:
BrazilianPortuguese Korean
English MandarinChinese
French Persian(Farsi)
German Russian
Hebrew Spanish
Hindi Turkish
Japanese Vietnamese
WeusetheSpanishandEnglishsamples,butmakeallofthemavailableindata general/.