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A comparison of three speaker-intrinsic vowel formant frequency normalization algorithms for sociophonetics

  • Anne H. Fabricius (a1), Dominic Watt (a2) and Daniel Ezra Johnson (a2)

This article evaluates a speaker-intrinsic vowel formant frequency normalization algorithm initially proposed in Watt & Fabricius (2002). We compare how well this routine, known as the S-centroid procedure, performs as a sociophonetic research tool in three ways: reducing variance in area ratios of vowel spaces (by attempting to equalize vowel space areas); improving overlap of vowel polygons; and reproducing relative positions of vowel means within the vowel space, compared with formant data in raw Hertz. The study uses existing data sets of vowel formant data from two varieties of English, Received Pronunciation and Aberdeen English (northeast Scotland). We conclude that, for the data examined here, the S-centroid W&F procedure performs at least as well as the two speaker-intrinsic, vowel-extrinsic, formant-intrinsic normalization methods rated as best performing by Adank (2003): Lobanov's (1971) z-score procedure and Nearey's (1978) individual log-mean procedure (CLIHi4 in Adank [2003], CLIHi2 as tested here), and in some test cases better than the latter.

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Adank, Patti. (2003). Vowel normalization: A perceptual-acoustic study of Dutch vowels. Ph.D. thesis, Katholieke Universiteit Nijmegen.
Adank, Patti, Smits, Roel, & van Hout, Roeland. (2004). A comparison of vowel normalization procedures for language variation research. Journal of the Acoustical Society of America 116:30993107.
Bigham, Douglas. (2008). Dialect contact and accommodation among emerging adults in a university setting. Ph.D. thesis, The University of Texas at Austin.
Cohen, Ayala. (1990). Graphical methods for testing the equality of several correlated variances. The Statistician 39(1):4352.
Deterding, David. (1990). Speaker normalization for automatic speech recognition. Ph.D. thesis, University of Cambridge.
Deterding, David. (1997). The formants of monophthong vowels in Standard Southern British English Pronunciation. Journal of the International Phonetic Association 27:4755.
Disner, Sandra. (1980). Evaluation of vowel normalization procedures. Journal of the Acoustical Society of America 67:253261.
Fabricius, Anne. (2007a). Variation and change in the trap and strut vowels of RP: A real time comparison of five acoustic data sets. Journal of the International Phonetic Association 37(3):293320.
Fabricius, Anne. (2007b). Vowel formants and angle measurements in diachronic sociophonetic studies: Foot-fronting in RP. Proceedings of the 16th International Congress of Phonetic Sciences, Saarbrücken. 14771480. Available at:
Fabricius, Anne, Watt, Dominic, & Johnson, Daniel E. (2008). A new speaker-intrinsic vowel formant frequency normalization algorithm for sociophonetics. Paper presented at Acoustics08, Paris.
Fabricius, Anne, Watt, Dominic, & Yurkova, Jillian. (2008). A new speaker-intrinsic vowel normalisation algorithm for sociophonetics. Paper presented at BAAP 2008, University of Sheffield.
Fox, Robert A., & Jacewicz, Eva. (2008). Analysis of total vowel space areas in three regional dialects of American English. Journal of the Acoustical Society of America 123(5):3068.
Hawkins, Sarah, & Midgley, Jonathan. (2005). Formant frequencies of RP monophthongs in four age groups of speakers. Journal of the International Phonetic Association 30:6378.
Hindle, Donald. (1978). Approaches to vowel normalization in the study of natural speech. In Sankoff, D. (ed.), Linguistic variation: Models and methods. New York: Academic Press. 161171.
Kamata, Miho. (2008). An acoustic sociophonetic study of three London vowels. Ph.D. thesis, University of Leeds.
Koopmans–van Beinum, Florien J. (1980). Vowel contrast reduction: An acoustical and perceptual study of Dutch vowels in various speech conditions. Ph.D. thesis, University of Amsterdam.
Labov, William. (1994). Principles of linguistic change, volume 1: Internal factors. Oxford: Blackwell.
Labov, William, Ash, Sharon, & Boberg, Charles. (2006). The atlas of North American English: Phonology, phonetics, and sound change. Berlin: Mouton de Gruyter.
Lobanov, Boris M. (1971). Classification of Russian vowels spoken by different speakers. Journal of the Acoustical Society of America 49(2B):606608.
Mesthrie, Rajend. (unpublished manuscript). Socio-phonetics and social change: Deracialisation of the goose vowel in South African English. Submitted.
Moreiras, Caroline. (2006). An acoustic study of vowel change in female adult speakers of RP. B.A. thesis, University College London.
Nearey, Terry. (1978). Phonetic feature systems for vowels. Ph.D. dissertation, University of Alberta. (published 1978, Indiana University Linguistics Club).
Rosner, Burton S., & Pickering, John B. (1994). Vowel perception and production. Oxford: Oxford University Press.
Thomas, Erik R. (2001). An acoustic analysis of vowel variation in New World English. Publication of the American Dialect Society 85. Durham, NC: Duke University Press.
Thomas, Erik R. (2002). Instrumental phonetics. In Chambers, J. K., Trudgill, P., & Schilling-Estes, N. (eds.), The handbook of language variation and change. Oxford: Blackwell. 168200.
Thomas, Erik R., & Kendall, Tyler. (2007). NORM: The vowel normalization and plotting suite. Available at:
Traunmüller, Hartmut. (1990). Analytical expressions for the tonotopic sensory scale. The Journal of the Acoustical Society of America. 88(1):97100.
Traunmüller, Hartmut. (1997). Auditory scales of frequency representation. Available at:
Watt, Dominic, & Fabricius, Anne. (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 9:159173. Available at:
Watt, Dominic, Fabricius, Anne, & Kendall, Tyler. (forthcoming). More on vowels: Plotting and normalization. In di Paolo, M. & Yaeger-Dror, M. (eds.), Sociophonetics: A student's guide. London: Routledge.
Watt, Dominic, & Tillotson, Jenny. (2001). A spectrographic analysis of vowel fronting in Bradford English. English World-Wide 22(2):269302.
Watt, Dominic, & Yurkova, Jillian. (2007). Voice onset time and the Scottish Vowel Length Rule in Aberdeen English. Proceedings of the 16th International Congress of Phonetic Sciences, Saarbrücken, Germany. 1521–124. Available at:
Wells, John C. (1982). Accents of English. 3 vols. Cambridge: Cambridge University Press.
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Language Variation and Change
  • ISSN: 0954-3945
  • EISSN: 1469-8021
  • URL: /core/journals/language-variation-and-change
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