8th International Seminar on Speech Production 421

An Aerodynamic Explanation for the Uvularization of Trills?

RyanK.Shosted Universityof Illinois at Urbana-Champaign E-mail: [email protected]

Abstract yetthe replacement of apical//byuvular /ö/ is well- attested.The reverse process is unknown. The origin of the uvular trill [ö] in the languages Numerous articulatory andacoustic-perceptual of Western Europe is a matter of some debate. The hypotheses have been put forward to explain the diachronic change from an alveolar trill to a uvu- relationship between the trills(e.g.[1,11,3,4]). lar trill is widely believed to be standard and the These discussions often considertheentire “rhotic” reverse process seems unattested. The present study class, which includes as well as trills. approaches this diachronic asymmetry by examining The thrust ofsuch arguments has been to unite the aerodynamics of uvular and alveolar trills pro- all rhotics using principledphoneticcriteria (e.g. duced under laboratory conditions. [22, 11, 4]). Unlike these studies, this paper will concentrateexclusively on the trills. From an articulatory point of view,there are sev- 1 Introduction eral structuresin the vocal tractthat canbe po- sitionedin such a way so as to give rise to an Despite its presence in German andFrench,two aerodynamically-driven, oscillatory soundsource. well-studied Western Europeanlanguages, the uvu- These include the vocal folds [24],theepiglottis lar trill is a relatively rare soundinhumanlanguage. [21],the uvula, the tongue tip, andthe lips [10]. Of The trill appears inAbkhaz (Northwest Caucasian), these possibilities, only the uvular and apical trills Batak (Austro-Tai), Moghol (Ural-Altaic), Ashke- alsohappen tobe lingual. Hence,the kinematic and nazic and TiberianHebrew,some dialects of Italian, physiological relationship between uvular and api- Portuguese, Caribbean Spanish, Dutch,andSwedish cal trills maynot beentirely surprising, since they [13, 10,8,7, 14, 1, 4]. Unspecified“back /r/”(which are composed ofasimilar source vibration andare mayor maynot be realizedasauvular trill)isre- produced with the tongue as a primary articulator. portedin Estonian andCzech [4]. From an acoustic-perceptual point of view,ithas One long-observedphenomenon is the interaction been demonstratedthat thefilter characteristics of of apical anduvular trills. For example,ithas been uvular and apical trillsare different(e.g. they do notedthat few,ifany, languages contrast the two notshare lowered F3) [11]. Asafirst pass, it may phonemically andthat there isatypologicalbias fa- be arguedthat speakers key in to the source rather voringthe apical trill [10, 23, 6,4,13]. It has also than the filter ofthe trill when they “misreconstruct” beennotedthat inWestern Europeanlanguages, at (to use [4]’sterm)aheard apical trill as a uvu- least, the diachronic tendency is to uvularize apical lar.However, a filter-based explanation forthe con- trills ratherthan apicalize uvulars [1]. For example, fusion ofdorsal and coronal rhotic approximants the alveolar trill is still heard in rural parts of France has alsobeen forwarded.The results, which sug- andCanada, but youngerspeakers are shiftingto a gest that speakers re-map the articulatory configura- uvular variant [5, 18]. tion ofrhotics based on perceptual ambiguity in the The relationship of apical anduvular trills has F2–F3 space, may apply generally to trillsaswell, captured attention because the sounds donotshare though this has not yet beenverified [4]. a common formant structure (e.g. F3 lowering) [11] Sociolinguistic arguments are also common in the

ISSP 2008 8th International Seminar on Speech Production 422

discussion of apical anduvular trills, though they are sure in the channelcan draw the uvulatowards the necessarily more concerned with the transmission of tongue, which the uvulathen strikes. Momentary sound change ratherthan its phonetic bases.Tothe contact between the two articulators is disrupted by extentthat transmission can trumpphoneticnatural- mountingpressure behindthe uvula.High-speed air ness, however, such facts must not be disregarded. flow once againlowers the pressure in the channel The sociolinguistic debate over /ö/has to dowith andthe cycle repeats itself. the geographicorigins ofthe soundand its subse- It has been shown that the production of trillsis quent spread throughout Western Europe. Eitherthe sensitive to intra-oral air pressure andthat excessive uvular trill spread as a prestige variantfrom France air flow can resultin frication ratherthan trilling [19, to Germany and beyond oritcroppedupin a number 20]. [12] concludes, “Since several factors have to of locationsindependently [7,4]. be withincriticallimits forthe vibration to occur it The factthat uvularization of apical trillsisnot is not surprisingthat trilling quite often failsto take well attested outside of Western Europe may sup- place andinstead a uvular or port the monogenetichypothesis. Polygeneticmod- is pronounced” (32). els, on the other hand, assume that the uvulariza- It has not been conclusively demonstratedthat the tion of apical trillsisanatural phonetic phenomenon uvula vibrates more quickly than the tongue tip [10]. which does notrequire the force ofprestige orso- The best evidence to this effect could be obtained cial contacttobe realized. Supporters ofthe poly- from speakers ofalanguage that supports a phone- geneticmodel should be concerned with the typo- mic distinction betweenboth kinds of trills (as noted logical scarcityofuvular trillsandthe geographic above,such langugesare difficult, if notimpossible, limitations on the /r/ > /ö/ sound change. to find). Nevertheless, [11] reports an average vibra- The present studywill contribute to these ongo- tory rate of30.5 Hz foruvulars in Southern Swedish, ing discussionsabout the phoneticnaturalness of while [9] report a meanvibratory rate of 26.2 Hz in rhoticsandthe transmission of /r/ > /ö/byaddress- Southern Swedish and Italian. [10] findthese mea- ingasmaller, though related issue: the aerodynam- surestobe statistically indistinguishable from the vi- ics ofuvular and apical trills.The paper will con- bration rates associated withmeasured apical trills sideraerodynamic explanationsfor why the change (around 28.6 Hz). /ö/ > /r/ appears unattested, even inlanguages where the uvularization of trills has been in effectforsev- eralhundred years [7]. Some hypotheses take into 3 Methods account confusion of /r/ in Parisian French with an- other apical sound, /z/, necessitatingthe move to/ö/ To explore the source characteristics ofuvular [17, 7]. While [17] considers the sound change grad- trills, a trainedphonetician and near-native speaker ual, [7] arguesitoccurredabruptly,assoon as the ofPortuguese (the author) produced sustaineduvu- structuralopposition of /r/ and /z/became threate- lar and apical trillsin a laboratory setting us- need.[1] providesafunctional explanation of /r/ ingasplit flow air mask (Glottal EnterprisesS/T- > /ö/bycitingthe needfor “as much freedom of MA1) connectedto a heated low-flow pneumotach the tongue as possible”inorderto avoid consonan- (Biopac, TSD137F) and differential pressure trans- talcoarticulation of , a motivation he claims ducer (Biopac, TSD160A). Signals were high-pass tobe particularly strongin French (564). filteredat10Hz usingaKrohn-Hite analog fil- ter. Fifty repetitions ofthe apical anduvular trills 2 Aerodynamics of trills were producedatone second each,followed by a two-second pause.The analog signals were digi- X-ray studies have shown that in French andGer- tizedat20 kHz andthen processedinMatlab toob- man,atleast, the uvular trill is produced by retract- tain the fundamental frequency (through autocorre- ingthe tongue root, liftingthe tongue body,and lation)andperiodograms.The resulting data give movingthe uvulaforward, perhaps through contrac- a more focusedpicture ofthe source characteristics tion of musculus uvulae [2, 24]. If air movesthrough that characterize and differentiate uvular and apical the channel at sufficientspeed, resulting low pres- trills.

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4 Results 40 Figures1and 2 presentsome typicaloral flow 35 signalsandaccompanyingperiodogramsforthe api- 30 cal anduvular trillsin the production database.The 25 20

first difference tonote are the differing vibrational Vibration rate (Hz) 15 rates.Autocorrelation ofthe two signals puts the average vibration forthe uvulars at 32.7 Hz (SD = apical uvular 5.2)andthe apicalsat24.9 Hz (SD = 4.1).While Figure 3: Vibration rates of uvular and apical trills. thefindings should be treated withcaution,since they are notproduced by a native speaker ofalan- guage with trills, they closely approximate the range The spectralcharacteristics ofthe uvular and api- of vibration ratesreportedforSouthern Swedish and cal source vibrationsare also strikingly dissimilar. confirm the suggestion that the uvula vibrates more There are more high frequency peaks in the spectra rapidly than the tongue tip [11]. Statistical analysis ofthe uvulars, indicative ofamore complexmode ofthe two vibration rate distributionsindicatesthat of vibration (note that the use ofthe aerodynamic they are significantly different F (1, 98) = 68.05, technology greatly reducestheeffect ofthe anterior p<0.001 (see Figure 3). filter on the signal[16]).The airflow is alsolower duringthe uvular trills, suggestingreducedintraoral Alveolar trill 1.5 pressure.

1

0.5

Oral (v) 0 5 Conclusion and discussion

−0.5

−1 0.5 0.55 0.6 0.65 Time (sec) In light ofthesefindings, it it temptingto argue Periodogram Power Spectral Density Estimate 0 foran additional functionalmotivation behind /r/ −20 > /ö/, one that incorporates new information about −40

−60 their aerodynamiccharacteristics.However, such a −80 hypothesis is not without complications of its own.

Power/frequency (dB/Hz) −100 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 Frequency (kHz) Uvular trills maybenefitfrom a marginal evolution- ary edge over apical trillsin terms of air expenditure. However, this line ofreasoningistenuous foranum- Figure 1: Oral flow signal with accompanying spec- ber ofreasons. First, high airflow sounds like frica- tral decomposition for the apical/alveolar trill. tivesare not rare in the world’s languages norisit clear that speakers implementsome strategy for con-

Uvular trill serving airflow duringspeech. Second, uvular trills 1.5

1 are sometimesrealizedasuvular , which 0.5 expendgreater airflow than apical trills, effectively Oral (v) 0 defeatingany drive for conservation. Finally, expen- −0.5

−1 0.5 0.55 0.6 0.65 ditures of airflow (with regard to totallung volume) Time (sec) Periodogram Power Spectral Density Estimate duringspeech utterancesare relatively small and can 0

−20 be manipulated adroitly—even reversed, in the case −40 ofingressive sounds.There is in fact a strongaero- −60 dynamic reason why apical trillsshould not be uvu- −80

Power/frequency (dB/Hz) −100 larized: the aerodynamicvoicing constraint [15]. 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 Frequency (kHz) Because the uvular trill is articulatedatamore pos- teriorplace than the apical trill, vocal fold vibration Figure 2: Oral flow signal with accompanying spec- is less likely tobe continuous, which naturally re- tral decomposition for the uvular trill. sults in devoicingand frication ofthe trill [20]. Thus, the prospectus foran aerodynamic ex-

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planation ofuvularization is still unclear, andde- [9] P. Ladefoged, A. Cochran,andS. F. Disner. Later- pends crucially on more aerodynamic investigations alsand trills. Journal of the International Phonetic into the airflow properties of otherspeech sounds. Association, 7:46–54, 1977. For example,the change from a high-airflow, high- [10] P. Ladefogedand I. Maddieson. The Sounds of the World’s Languages. Blackwell, Oxford, 1996. pressure trill to a low-airflow, low-pressure trill may [11]M.Lindau.The storyof /r/. In V. A. Fromkin, edi- be viewedasakind of lenition analogous to conso- tor, Phonetic Linguistics: Essays in Honor of Peter nant spirantization, e.g. /b/ > /B/,ifrelatively high- Ladefoged, pages157–168, New York, 1985.Aca- pressure voicedstop indeed become rel- demic Press. atively low-pressure voiced fricatives.While aero- [12] I. Maddieson. Uvular consonants. InM.Haspel- dynamics maynot be able to explain the prevalence math, M. S. Dryer, H.-J. Bibiko,D. Gil,B. Com- of trill uvularization inWestern Europe,itprovides rie,andC. Schmidt, editors, The World Atlas of Language Structures, pages30–31, Oxford.Oxford additional information forunderstandingthe pho- University Press. neticbasesand transmission ofthe sound change. [13]I.Maddieson and K. Precoda.UPSIDand PHONEME version 1.1, 1992. UniversityofCali- 6 Acknowledgments fornia at Los Angeles. [14]M.H.Mateus andE. d’Andrade. The Phonology Iwould like to thank Jos´e Hualde, JenniferCole, of Portuguese.Oxford University Press, Oxford, and ZsuzsannaFagyal forgenerously sharing with 2000. me their thoughts on this topic. Any mistakes or [15] J.J.Ohala.The originofsound patternsinvocal tract constraints.InP. F.MacNeilage, editor, The omissionsare my own. Production of Speech, pages 189–216,New York, 1983. Springer-Verlag. References [16] M. Rothenberg.Measurement of airflow in speech. Journal of Speech and Hearing Research, 20:155– [1] P. Delattre. A contribution to the historyof r 166,1977. grasseye´. Modern Language Notes, 59(8):562–564, [17] J. Rousselot. Dictionnaire de laprononciation 1944. franc¸aise.InRevue Phonetique´ , 1911-1915. [2] P. Delattre. Pharyngeal featuresin the consonants [18] G. Sankoff, H. Blondeau, and A. Charity. In- of ,German, Spanish,French,and American dividual rolesin areal-time change: Montreal English. Phonetica, 23:129–155, 1971. (r > ö) 1947–1995. InH.van de Velde and [3] D. Demolin. Some phonetic andphonologicalob- R.vanHout, editors, r-atics: Sociolinguistic, Pho- servationsregarding /ö/. In H. van de Velde and netic and Phonological Characteristics of /r/, pages R.vanHout, editors, r-atics: Sociolinguistic, Pho- 141–158, Bruxelles, 2001. Etud´ es et Travaux. netic and Phonological Characteristics of /r/, pages [19]M.-J. Sol´e.The phoneticbasis ofphonological ´ 63–73, Bruxelles, 2001. Etudes et Travaux. structure: The role ofaerodynamic factors.InPro- [4]O.Engstrand, J. Frid, andB. Lindblom. A percep- ceedings of the Ist Congress of Experimental Pho- tualbridge betweencoronal anddorsal/r/. In M.-J. netics, pages 77–94, Tarragona, 1999. Sol´e,P. S. Beddor, and M. Ohala, editors, Experi- [20] M.-J. Sol´e.Aerodynamiccharacteristics of trills mental Approaches to Phonology, pages175–191, andphonological patterning. Journal of Phonetics, Oxford, 2007. Oxford University Press. 30:655–688, 2002. [5] Z. Fagyal,D.Kibbee,andF.Jenkins. French: [21]A.Traill. Phonetic and Phonological Studies of A Linguistic Introduction. Cambridge University !Xo´o˜ Bushman. Number5inQuellen zur Khoisan- Press, Cambridge, 2006. Forschung.Helmut Buske, Hamburg, 1985. [6] T. Goeman and H. van de Velde. Linguistic and [22] H. van de Velde andR.vanHout. r-atics: Soci- geographicalco-occurrence constraints on /r/ and olinguistic, Phonetic, and Phonological Character- /G/ in Dutch dialects. InH.van de Velde and istics of /r/. Etud´ es et Travaux, Bruxelles, 2001. R.vanHout, editors, r-atics: Sociolinguistic, Pho- [23] L.Walsh Dickey. The Phonology of Liquids. PhD netic and Phonological Characteristics of /r/, pages thesis, Universityof Massachusetts at Amsherst, 91–112, Bruxelles, 2001. Etud´ es et Travaux. [7] E. F.Haden. The uvular r in French. Language, 1997. [24]W.R. Zemlin. Speech and Hearing Science: 31(4):504–510, 1955. [8] G.Khan. TiberianHebrew Phonology. In A. S. Anatomy and Physiology. Allyn andBacon, Kaye, editor, Phonologies of Asia and Africa, vol- Boston,4th edition, 1998. ume 1, pages85–102, Winona Lake, IN, 1997. Eisenbrauns.

ISSP 2008