The aim of the present report was to explore whether vowel metrics, demonstrated to distinguish dysarthric and healthy speech in a companion article (Lansford & Liss, 2014), are able to predict human perceptual performance.


Vowel metrics derived from vowels embedded in phrases produced by 45 speakers with dysarthria were compared with orthographic transcriptions of these phrases collected from 120 healthy listeners. First, correlation and stepwise multiple regressions were conducted to identify acoustic metrics that had predictive value for perceptual measures. Next, discriminant function analysis misclassifications were compared with listeners' misperceptions to examine more directly the perceptual consequences of degraded vowel acoustics.


Several moderate correlative relationships were found between acoustic metrics and perceptual measures, with predictive models accounting for 18%–75% of the variance in measures of intelligibility and vowel accuracy. Results of the second analysis showed that listeners better identified acoustically distinctive vowel tokens. In addition, the level of agreement between misclassified-to-misperceived vowel tokens supports some specificity of degraded acoustic profiles on the resulting percept.


Results provide evidence that degraded vowel acoustics have some effect on human perceptual performance, even in the presence of extravowel variables that naturally exert influence in phrase perception.


  • Bigham, D. (2008). Dialect contact and accommodation among emerging adults in a university setting (Doctoral dissertation).University of Texas at Austin.
  • Bradlow, A., & Bent, T. (2002). The clear speech effect for non-native listeners.The Journal of the Acoustical Society of America, 112, 272–284.
  • Bunton, K., & Weismer, G. (2001). The relationship between perception and acoustics for a high-low vowel contrast produced by speakers with dysarthria.Journal of Speech, Language, and Hearing Research, 44, 1215–1228.
  • Flynn, N. (2011). Comparing vowel formant normalization procedures.York Working Papers in Linguistics (Series 2), 11, 1–28.
  • Gertsman, L. (1968). Classification of self-normalized vowels.IEEE Transactions on Audio Electroacoustics, AU-16, 78–80.
  • Higgins, C., & Hodge, M. (2002). Vowel area and intelligibility in children with and without dysarthria.Journal of Medical Speech & Language Pathology, 10, 271–277.
  • Hillenbrand, J. M., Getty, L. A., Clark, M. J., & Wheeler, K. (1995). Acoustic characteristics of American English vowels.The Journal of the Acoustical Society of America, 97, 3099–3111.
  • Kent, R. D., Weismer, G., Kent, J. F., & Rosenbek, J. C. (1989). Toward phonetic intelligibility testing in dysarthria.Journal of Speech and Hearing Disorders, 54, 482–499.
  • Kent, K., Weismer, G., Kent, J., Vorperian, H., & Duffy, J. (1999). Acoustic studies of dysarthric speech: Methods, progress and potential.Journal of Communication Disorders, 32, 141–186.
  • Kim, H., Hasegawa-Johnson, M., & Perlman, A. (2011). Vowel contrast and speech intelligibility in dysarthria.Folia Phoniatrica et Logopaedica, 63, 187–194.
  • Kim, Y.-J., Weismer, G., Kent, R. D., & Duffy, J. R. (2009). Statistical models of F2 slope in relation to severity of dysarthria.Folia Phoniatrica et Logopaedica, 61, 329–335.
  • Kutner, M., Nachtsheim, C., Neter, J., & Li, W. (2005). Applied linear statistical models (5th ed.). New York, NY: McGraw-Hill/Irwin.
  • Labanov, B. M. (1971). Classification of Russian vowels spoken by different speakers.The Journal of the Acoustical Society of America, 49, 606–608.
  • Lansford, K. L., & Liss, J. M. (2014). Vowel acoustics in dysarthria: Speech disorder diagnosis and classification.Journal of Speech, Language, and Hearing Research. Advance online publication. doi:10.1044/1092-4388(2013/12-0262)
  • Lindblom, B. (1963). Spectrographic study of vowel reduction.In R. D. Kent, J. L. Miller, & B. S. Atal (Eds.), Papers in speech communication: Speech perception (pp. 517–525). New York, NY: The Acoustical Society of America.
  • Liu, H. M., Tsao, F. M., & Kuhl, P. K. (2005). The effect of reduced vowel working space on speech intelligibility in Mandarin-speaking young adults with cerebral palsy.The Journal of the Acoustical Society of America, 117, 3879–3889.
  • McRae, P. A., Tjaden, K., & Schoonings, B. (2002). Acoustic and perceptual consequences of articulatory rate change in Parkinson disease.Journal of Speech, Language, and Hearing Research, 45, 35–50.
  • Nearey, T. M. (1989). Static, dynamic, and relational properties in vowel perception.The Journal of the Acoustical Society of America, 85, 2088–2112.
  • Neel, A. T. (2008). Vowel space characteristics and vowel accuracy.Journal of Speech, Language, and Hearing Research, 51, 574–585.
  • Payton, K., Uchanshki, R., & Braida, L. (1994). Intelligibility of conversational and clear speech in noise and reverberation for listeners with normal and impaired hearing.The Journal of the Acoustical Society of America, 95, 1581–1592.
  • Peterson, G. E., & Barney, H. L. (1952). Control methods used in a study of the vowels.The Journal of the Acoustical Society of America, 24, 175–184.
  • Picheny, M., Durlach, N., & Braida, L. (1985). Speaking clearly for the hard of hearing: I. Intelligibility differences between clear and conversational speech.Journal of Speech and Hearing Research, 28, 96–103.
  • Sapir, S., Ramig, L., Spielman, J., & Fox, C. (2010). Formant centralization ratio (FCR) as an acoustic index of dysarthric vowel articulation: Comparison with vowel space area in Parkinson disease and healthy aging.Journal of Speech, Language, and Hearing Research, 53, 114–125.
  • Sapir, S., Spielman, J., Ramig, L., Story, B., & Fox, C. (2007). Effects of intensive voice treatment (the Lee Silverman Voice Treatment [LSVT]) on vowel articulation in dysarthric individuals with idiopathic Parkinson disease: Acoustic and perceptual findings.Journal of Speech, Language, and Hearing Research, 50, 899–912.
  • Strange, W. (1989a). Dynamic specification of coarticulated vowels spoken in sentence context.The Journal of the Acoustical Society of America, 85, 2135–2153.
  • Strange, W. (1989b). Evolving theories of vowel perception.The Journal of the Acoustical Society of America, 85, 2081–2087.
  • Tjaden, K., & Wilding, G. E. (2004). Rate and loudness manipulations in dysarthria: Acoustic and perceptual findings.Journal of Speech, Language, and Hearing Research, 47, 766–783.
  • Turner, G., Tjaden, K., & Weismer, G. (1995). The influence of speaking rate on vowel space and speech intelligibility for individuals with amyotrophic lateral sclerosis.Journal of Speech and Hearing Research, 38, 1001–1013.
  • Uchanski, R. M., Choi, S. S., Braida, L. D., Reed, C. M., & Durlach, N. I. (1996). Speaking clearly for the hard of hearing: IV. Further studies of the role of speaking rate.Journal of Speech and Hearing Research, 39, 494–509.
  • Watt, D., & Fabricius, A. (2002). Evaluation of a technique for improving the mapping of multiple speakers' vowel spaces in the F1∼F2 plane.Leeds Working Papers in Linguistics and Phonetics, 9, 159–173.
  • Weismer, G., Jeng, J.-Y., Laures, J., Kent, R. D., & Kent, J. F. (2001). Acoustic and intelligibility characteristics of sentence production in neurogenic speech disorders.Folia Phoniatrica et Logopaedica, 53, 1–18.
  • Weismer, G., & Martin, R. (1992). Acoustic and perceptual approaches to the study of intelligibility.In R. D. Kent (Ed.), Intelligibility in speech disorders: Theory measurement and management (pp. 67–118). Amsterdam, the Netherlands: John Benjamin.
  • Whitehill, T. L., Ciocca, V., Chan, J. C.-T., & Samman, N. (2006). Acoustic analysis of vowels following glossectomy.Clinical Linguistics & Phonetics, 20, 135–140.

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