The variability of early accent peaks in Standard German

24 Pages·2010·0.77 MB·English

The variability of early accent peaks
in Standard German
Tamara Rathcke and Jonathan Harrington
Thispaperis concernedwiththerelationships between‘early’pitch accentsin
German and with whether downstep in German is phonological or phonetic.
Atthe coreof our analysis isan investigation into thedifferences betweentwo
kinds of pitch accents in which the pitch peak precedes the accented vowel:
theseareH+!H*andH+L*whichareclaimedtobephonologicallycontrastive
in German. We made use of two experimental procedures: (1) a production
experiment in which speakerswere askedto imitate synthetically manipulated
sentences and (2) a semantic differential experiment in which listeners rated
the perceived meaning of those sentences on eight semantic scales.Although
boththeimitationandperceptionexperimentprovidedevidenceforadistinction
between an early and a later (H*) peak accent, the results pointed neither to
a three-way distinction, nor to a categorical distinction between H+!H* and
H+L*. Finally, we present some results from an analysis of both English and
Germancorporawhichsuggestthatthedifferencebetweenthesetwopeaksmay
be phonetic and attributable to the number of syllables following the nuclear
accent in the tail. Based on these results and from theoretical considerations,
wearguethatH+!H*isaninappropriatepitchaccentcategoryintheinventory
ofparadigmatic phonological intonational contrasts ofstandard German.
1. Introduction
Theautosegmental-metrical(AM)theoryofintonationrestsonthepremisethat
anf0-contour isderived fromasequenceofabstractphonological tone-targets
thataresystematicallyalignedwithsegmentalunits(Pierrehumbert1980,Beck-
manandPierrehumbert1986, Ladd1996).Thetonal inventory is reducedtoa
basicdistinctionbetweenH(igh)andL(ow)tonesandastarrednotationisused
in pitch accents to indicate the phonological association between a tone and
a rhythmically strong syllable, which in turns has a major influence on their
temporal alignment. In one sense, temporal alignment is clearly phonological
because it is the result of the way that the tune is associated with the text, but
534 TamaraRathckeandJonathanHarrington
inanotheralignmentisalsocontext-dependentandphoneticasvariousexperi-
mentshaveshown(SilvermanandPierrehumbert1990).Thefrequencyscaling
ofthe High andLow tones is assumedto be predictablefromphonetic factors
and controlled by a system of rules. As Liberman and Pierrehumbert (1984)
have argued,downstep is oneof themechanismsusedto justify theadherence
toatwo-tonemodelinthefaceofwhatareevidentlymanydifferentf0-levelson
the surface.Thus, in the famous stepping contour, the progressive lowering of
f0-levelsonthestrong syllablesofsuccessiveaccentedwordscanbemodelled
by downstep that is iteratively (and in theory infinitely) applied to a H* tone
withinasinglephrase.Thisspecificationofdownstep isclearlyphonetic.
However, it has often been difficult to place ‘downstep’ along the divide
betweenphonological categoriesandphonetic implementation. Downstep was
originallyinvokedintonelanguagestoexpresstheideathatthereisahightone
thatisautomaticallylowered afteralowtoneinanH-L-Hsequenceandinthe
AMmodel,downstepreferstotheloweringofsuccessivehightonetargetswithin
a prosodic phrase. Unlike Liberman and Pierrehumbert (1984), Ladd (1996:
97) argues that there is also evidence that downstep is largely an ‘orthogonal
phonologicalvariable’withthemeaningof‘finality’or‘completeness’(cf.Ladd
1996:90–92; thiswasalsoarguedinLadd1983).
ThedownsteppedpitchaccentsinAmericanEnglishincludemonotonal!H*
andbitonalL+!H*(BeckmanandAyers1994).Sincetheynecessarilyfollowa
non-downstepped and often bitonal accent, these downstepped accents cannot
occurinphrase-initialposition. Ourinterestliesinathirdtypeofdownstepped
pitchaccentH+!H*whicharoseintheevolutionoftheToBIsystem,basedonthe
AMmodel,fortranscribingstandardAmericanEnglishintonation. IntheToBI
system,H+L*cametobereplacedbyH+!H*(Ladd1996:96–97;Gussenhoven
2004: 132) both for phonetic reasonsand becausethe levelof thestarred tone
was not usually at the bottom of the speaker’s range, as would be expected if
the second component of this bitonal accentwere actually L*. Given that one
pitchaccentessentiallyreplacesanotherintheToBIsystem,thereisobviously
nosenseinwhichtheycanbephonologically contrastiveinAmericanEnglish.
However, the researchon intonational phonology by Grice(1995)in Southern
British English and by Grice and Baumann (2002) and Grice, Baumann and
Benzmüller (2005) in standard German does provide evidence that there may
indeedbeacontrastbetweenH+L*andH+!H*anditisthisaspectthatwewish
toexploreforGermanusingacousticandperceptualtechniques.
SomeexamplesofthiscontrastarepresentedintheGermanGToBItraining
materials(Benzmüller,GriceandBaumannURL2).InbothH+L*andH+!H*,
thereisapitchpeakduetotheH+thatprecedestheaccentedvowel:thediffer-
encebetweenthesepitchaccentsisthatinH+L*alowpitchtargetisreachedin
ThevariabilityofearlyaccentpeaksinStandardGerman 535
theaccentedvowel,whereasinH+!H*thereisadownsteppedpeak thatoccurs
duringtheaccentedvowel,sothatthetargetstepisfromhightomidinH+!H*
butnotinH+L*.ThisisfurtherillustratedinFig.1whichshowsanH+L*pitch
accentonschräg (‘diagonally’)intheleftpanelandanH+!H*pitchaccenton
schön (‘pretty’) in the right panel.There is a markedstep down in pitch from
theprecedingsyllabletoapitch-troughthatoccursduringthe[E]ofschräg;on
the other hand, there is no evidence of a trough in the [2] vowel of schön and
the pitch does not reachthe bottom ofthe speaker’srangeasit does forH+L*
inschräg.
If we allow the system to contrast H+L* and H+!H* pitch accents, then
this meansthat the frequencyscaling of the(starred) tones that areassociated
with the accented syllable is no longer phonetic as argued in e.g., Pierrehum-
bert(1980),butisimplicitly phonologicalbecausethereisnowaparadigmatic
contrastbetweenthree tonallevels: high-starin(L+)H*,low-starinH+L*and
effectively a mid-star in H+!H*. Furthermore, H+!H* represents a departure
from thephonotactics ofdownstep discussed earlier,since – in contrast to the
other downstepped accents – there is no obligation for the H+!H* to follow a
pitch accent (as a result of which, H+!H*, unlike !H* or L+!H*, could be the
firstandindeedonlypitchaccentinaphrase).
Figure1. Synchronized time-waveform and f0-trajectory with word labels (top) and
GToBIlabelsofnuclearaccents(bottom)takenfromBenzmüller,Grice,and
Baumann(URL2)oftwoGermanutterances:... immernochweiterschräg.
(‘still further along diagonally’) and ... wie schön sie war. (‘how pretty it
was’).
Thereissomedifficultyinestablishingthemeaningdifferencesassociatedwith
thesepitchaccents.Baumann(pers.comm.)suggests thatH+L*mightconvey
areassuring,soothingtoneofvoiceincontrasttothegreatermatter-of-factness
or neutrality of H+!H*. In a previous study (Rathcke and Harrington 2006),
we assumed the general semantic differenceto be that between general/polite
536 TamaraRathckeandJonathanHarrington
(H+!H*)andresolute/self-evident (H+L*)statements, but wewerenot ableto
verifyanyofthesehypothesisedmeaning-tuneassociationsempirically.Further-
more,ourprevious studyshowed thatitwasverydifficult tofindanysemantic
contextdifferringbetweentheusageofH+!H*andH+L*.
InothermodelsoftheintonationofstandardGerman(e.g.,Féry1993;Kohler
1997),thereisclearevidenceforacontrastbetweenH*andH+L*(orH*Lvs.
HH*Lin Fe´ry’sanalysis), i.e. foracontrast oftiming in whichthe pitch peak
is synchronised near the temporal midpoint of the vowel in H* as opposed
to its muchearliersynchronisation with the immediatelyprecedingsyllable in
H+L*,buttherehavebeennosuggestionstoourknowledgethatthereisathree-
way phonological contrast between H* and what would be two types of early
peaks,H+L*andH+!H*.Wethereforehavetoconsiderthepossibility thatthe
distinction between H+L* and H+!H* may not be phonological but phonetic,
i.e. predictably relatedto factors such asphrasal position, number ofsyllables
andspeechrate.
Our basis for assessing whether the distinction between two pitch accents
is categoricalis firstly that native listeners canhearand reproducethedistinc-
tion andsecondly thatit isassociatedwith semanticdifferences.Since,forthe
reasons outlined above, it is difficult to be certain about the type of meaning
differencethat is likely to be associated with the pitch accent distinctions be-
ing investigated, the present paper draws upon a semantic differential test for
thispurpose (Osgood,Suci,andTannenbaum1957;Uldall 1964;Dombrowski
2003; Ambrazaitis 2005), in which listeners were asked to make judgements
on various semantic scales. We also carried out an imitation test of the kind
usedinPierrehumbertandSteele(1989)inwhichsubjectsimitatetokensfrom
acontinuumspanningthetonalcategoriesunderinvestigation.
WeusedtheH*pitch accentasacontrolstimulus andcreatedacontinuum
includingf0-trajectoriesofthethreepitchaccents:H*,H+!H*andH+L*.Ifthe
distinction between H+!H* and H+L* is categorical, then listeners should be
morelikely to perceive, and to produce, between- rather than within-category
differences. On the other hand, subjects’ responses will be bimodal due to a
contrastbetweenH*vs.acollapsedH+!H*/H+L*category,ifthelatterarejust
phonetic variants ofasingle ‘earlypeak’category. Similarly,we would expect
threedifferenttypesofresponsestothecontinuum inthesemanticdifferential
testifallthreepitchaccentsarephonologically distinct.
ThevariabilityofearlyaccentpeaksinStandardGerman 537
2. Experiment
2.1. Stimuli
Wecreatedasyntheticcontinuuminthef0-scalingdomainspanningthreepitch
accentcategories, H*,H+!H*and H+L*with the H*endof thecontinuum as
controlstimuli.Wechosetomakeourcontinuumspanthreeratherthanjusttwo
(H+!H*, H+L*) categories, because wewanted to makesure that therewas at
leastoneunequivocalcontrastrepresentedinthestimuli (i.e.,H*vs.H+L*).
The test sentence Sie mag Bananen (‘she likes bananas’) was read several
times by a femalespeaker as a simple statement with a nuclear accent on the
medialrhythmically strong syllable -na-inBananen.Theproduction inwhich
she producedthe finalweaksyllable -nenwith aschwaandin which thepitch
accentwasclearlyH+L*waschosenasthebasicitemforresynthesispurposes.
Thiswasdoneprimarilybecauseourpilotstudy(RathckeandHarrington2006)
had shown that tokens of Bananen with no final schwa vowel were often imi-
tatedwith acreakyvoiceextending fromsomepartoftheaccentedsyllable of
Bananentoitsoffset,therebymakingf0difficulttomeasure.
Theconstructionofthecontinuumwasbasedontheidea,proposedbyGrice
et al. (Griceand Baumann2002; Grice,BaumannandBenzmüller2005), that
themaindifferencesbetweenH*,H+!H*,andH+L*areinthef0-heightofthe
accentedvowel.Thecontinuumwasthereforedesignedtoextendoverthreecat-
egoriesfromH*throughH+!H*toH+L*byincrementingf0-heightvariations
in the accented vowel. More specifically, we created a stylised H+L* contour
fromthesubject’sactualproductionofH+L*bymakingthef0-contourfallover
theaccentedsyllable/na:/inastraightlinefromtheonsetoftheinitial[ν]at210
Hzto140Hzatapoint1/3ofthewayintothevowel.ForthisstylisedH+L*(st
16
inFigure2),thef0waskeptlevelat140Hztotheendof[a:].Twopoints(atthe
onset ofthe nuclearsyllable andattheoffsetofthe following nasal)remained
fixedintimeandfrequencyforallsynthesisedtokens.Thecontinuumwassyn-
thesisedbyraisingthef0-levelinfifteen0.5semitonestepsoverthemiddle1/3
sectionofthevowelandthenbyconnectingthebeginningandendofthisraised
sectionwithstraightlinesasshowninFigures2and3.Thisprocedureresulted
in 16 stimuli. Weassumedthat the firststimuli (st -st ) corresponded to H*
01 06
giventhatthef0dropfromtheinitial/ν/ofBananen(timepointref1inFigure2)
to themidpoint of /α:/ was less than 3 st, i.e. generally less than that required
forantonalfalltobeperceived(‘tHart1981).Thestimulist -st represented
07 11
clearfallsofbetween3and5stfromtheprecedinghighpeakatref1inFigure2
toamidrangedf0-areaintheaccentedvowel(i.e.,H+!H*).Thestimulist -st
12 16
corresponded totheacousticformoftheH+L*pitch accentdefinedasasteep
538 TamaraRathckeandJonathanHarrington
Figure2. Time-waveformwithwordandsegmentlabelsofthetestsentence(top)syn-
chronized with f0-trajectories of the first (st ) and the last (st ) stimulus
01 16
ofthecontinuum.Foralltokensfromthecontinuum,thetimeandfrequency
pointsmarkedbyref1andref2onthetimeaxiswerefixed.Theverticaldashed
linesmarktheintervaloverthemiddle1/3sectionofthevowelthatwasraised
insixteen0.5semitonesteps.
Figure3. Schematic outlineof the componentsthat makeup thestimuluscontinuum
andtheirpresumedassociationwiththepitchaccentsshownontheright.
fall of between 5.5 and7.5 st to the verylow f0-valuesnearthe bottom ofthe
speaker’srange(seealsoFigure3).
2.2. Semanticscales
The semantic differential measures subjects’ reactions to stimuli in terms of
ratingsonbipolarscalestypicallydefinedwithcontrastingadjectivesateachend.
Thelistofsemanticscalesresultinginasemanticdifferentialisprimarilychosen
based on hypotheses about the meaning of the categories under investigation.
As has been shown in various studies (e.g., Heise 1970), ratings on bipolar
scalestendtobecorrelated,andthethreebasicdimensionsofresponse(labelled
‘evaluation’, ‘potency’and ‘activity’) account for most of the co-variation in
ThevariabilityofearlyaccentpeaksinStandardGerman 539
ratings. By using a few pure scales like ‘good-bad’for evaluation, ‘powerful-
powerless’ for potency, and ‘fast-slow’ for activity, reliable measures can be
obtained ofsubjects’overallattitudinal responsestodifferentstimuli.
In contrast to the earlier semantic differential studies (e.g., Uldall 1964)
whichwerecharacterisedbyanaposteriori factoranalysisforthepurposesof
extractingtheunderlyingsemanticdimensions,acompletesemanticdifferential
including the basic semantic dimensions was constructed a priori (see e.g.,
Dombrowski 2003 and Ambrazaitis 2005 for more details). For the present
investigation, eight scaleswerecreated.Thechoiceofscaleswasbased onthe
following considerations:
1. Scales 1–3:These correspond to meaning contrasts that have already been
demonstratedfordistinctions analogoustoH*vs.H+L*(e.g.,Kohler1987;
2005).So,thesescaleswereselectedasthecontrolcondition.
2. Scale4:Thechoiceofthisscalewasinspiredbythefrequencycode(Ohala
1984):perhapsH+!H*isusedparalinguisticallytoavoidverylowf0-values
(whichareassumedtobetypicalforH+L*pitchaccents).Asiswellknown
(e.g.,Gussenhoven2002),lowtonestendtoconveyspeakers’dominanceor
tosignalunalterablefactsinagreatnumberoflanguages.
3. Scale 5: As outlined in the introduction, this scale’s semantic distinction
has alreadybeenhypothesised as oneoftheways that meaningdifferences
betweenH+!H*andH+L*maybeconveyed.
4. Scales6–8:Thesewereaddedtocompletethesemanticdifferentialwiththe
threebasisdimensions(evaluation,potency,activity,respectively).Arelevant
factorforthechoiceofcontrasting adjectivesforscale6isthatGriceetal.
(GriceandBaumann2002;Grice,BaumannandBenzmüller2005)consider
‘politeness’tobeoneofthemeaningsassociatedwiththeH+!H*vs.H+L*
distinction.Thesemanticcontrastschosenforthescales7and8werethought
tobegoodexponents of‘potency’and‘activity’indialogues.
The scalesareshown inTable 1.Taking into account the meaningdistinctions
associated with the frequency code (Ohala 1984) and what is known about
howmeaningdifferencesareconveyedbythedistinctions betweenH*,H+!H*
and H+L*(GriceandBaumann2002; Grice,Baumannand Benzmüller2005;
Kohler 1987, 2005), the negative pole of each scale was assumed to be more
appropriateforH+L*pitchaccents,thepositivepoleinscales1–3forH*,and
thepositivepoleofscales4–8forH+!H*pitchaccents.Scales1–3areassociated
primarilywithdifferencesoflinguistic meaning,whiletheotherscalesexpress
predominantly differencesofparalinguistic meaning(cf.Ladd1996:33–36).
Thescaleswereembeddedinacarriersentence‘Thespeakersoundslike...’.
Theinstructions to thesubjects forjudging the scalarvalues madeitclearthat
540 TamaraRathckeandJonathanHarrington
Table1. Eightpragmaticscaleschosenfortheperceptiontestwithsemanticdifferential.
Germantermsgivetheexactmeaningofthescalepolesusedinthetest.
Scale Negativepole(−) Positivepole(+)
no. Germanterm Englishtranslation Germanterm Englishtranslation
1 wissend knowing erkennend realising
2 abschließend concluding diskussions-eröffnend openingadiscussion
3 akzeptierend accepting kontrastierend refusing
4 resolut outofthequestion kompromissbereit readytocompromise
5 beruhigend calming ermunternd encouraging
6 unhöflich impolite höflich polite
7 sicher certain unsicher uncertain
8 gelangweilt bored interessiert interested
we were interested in potential meaning differences evoked by the speaker’s
melody.Althoughsemanticjudgementscanbeinfluencedbythemorpho-syntax
andlexisofanutterance,wedecidedtouseonlyonesentenceforthesemantic
differentialtestinordertolimitthelengthofthetestto30min.
2.3. Procedures
Atapecontaining128stimuliwascreatedfromeightrepetitions ofeachofthe
16 stimuli.Thus eachstimulus waspaired oncewith eachscale andpresented
inrandomisedorder.Thetapewasplayedtothesubjectswhohadtomarktheir
answers on a sheet of paper containing the scales. They also had to rank the
utterance between ±3, i.e. between the extreme negative and positive ends of
the scale.They were told to interpret these values as follows: 0 was ‘neutral’,
±1was‘slightly’(e.g.,assigning-1onscale8correspondsto‘slightlybored’),
±2was‘quite’,and±3‘extremely’.
Thesubjects wereinstructed to waitforthe auditory prompt precededby a
beepandtojudgespontaneouslyonthegivenscalehowtheythoughtthespeaker
sounded.Theydidthisforeachstimulusseparatedbya4spause.Theperception
task wasprecededby atrial session including eight stimuli presentations (one
for each scale) to familiarise the subjects with scales and with the procedure.
After the trial session the subjects had the opportunity to ask questions. The
stimuli were presented fromaCD-player in asound treated roomat the IPDS
Kiel.
Fortheimitationtest,thesixteenstimulidetailedabovewereeachcopiedten
times resulting in 160 items.These 160 items wererandomised and then each
presented twice with a preceding beep.After the second presentation of each
stimulus,therewasapauseduringwhichthesubjectwasinstructedtoimitateit,
paying particularattention tocopying themelodyascloselyaspossible. Inthe
ThevariabilityofearlyaccentpeaksinStandardGerman 541
event ofahesitation orspeecherror,theitemwasrepeated.Notimelimit was
imposedforresponses.Thestimuli werepresentedtosubjectsviaheadphones.
TheimitationtestwascarriedoutinasoundtreatedrecordingstudioattheIPDS
Kiel.
Twelve speakers of standard North German, five M and seven F between
20and22yearsofagewithoutknownspeechorhearingdisordersparticipated
intheexperiment.AllsubjectswerebeginnerstudentsofphoneticsattheIPDS
Kiel.Noneofthesubjectshadanyexperienceinprosodynorwastold thepur-
poseoftheexperiment.Allsubjectswerepaidforparticipation.Theexperiment
(containing bothsemanticandimitation test)tookaboutonehour.
2.4. Results
2.4.1. SemanticDifferential
If there is a separate range of meanings conveyed by H+!H* as opposed to
H* and H+L*, then we would expect to find a marked judgement profile for
stimuli 7–11 on any of the scales 4–8: that is, these stimuli should get high
positiveornegativescalevalueswhereasstimuli01–06aswellas12–16should
belabelled‘neutral’orwithscalevaluesoppositetothosefromstimuli 7–11.
The evaluation of the 16-point continuum is shown in Figure 4: the x-axis
representsthestimulusnumber(01–16)andthey-axisisthescalevalue(seven
points).Thedataforeachscalewereanalysedseparatelywith arepeatedmea-
sures analysis of variance using SPSS (Brosius 2002). The f0-level in the ac-
centedvowel(i.e.,stimulusnumber)wastheindependentvariableandthejudge-
ment score the dependent variable.We used a repeated measuresANOVA be-
cause the subjects judged more than one stimulus within one analysis. The
Greenhouse-Geisser correction for non-homogenity of variances was applied
(Leonhart 2004).These statistical results are summarised inTable 2.The sig-
nificancelevel(alpha)wassetat1%sincethesamplewasonlyn=12.
There weresignificant differencesin subject responses on five out of eight
scales, i.e. on scales 1–3 aswell as on scales 5 and 8 (Figure 4).As expected,
scales1–3showedchangesofjudgementthatarecompatiblewiththesemantic
differencesforthedistinction between‘medial’and‘early’peaks(Kohler1987
and 2005), corresponding roughly to the H* vs. H+L* difference in an AM
analysis.Scale5showssimilarresultsforscales1–3,i.e.themeaning‘soothing’
shows differencesprimarily between the beginning and end ofthe continuum,
andhencebetweenH*andH+L*andnot–ashypothesised –betweenthepart
of the continuum corresponding to the H+!H*vs. H+L* distinction (in which
case,wewouldhaveexpectedamajordifferencebetweenthemiddleandtheend
ofthecontinuum).Thesameistrueforscale8althoughtheprofileofjudgments
542 TamaraRathckeandJonathanHarrington
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