Speaker vowel formant normalization, a technique that controls for variation introduced by physical differences between speakers, is necessary in variationist studies to compare speakers of different ages, genders, and physiological makeup in order to understand non-physiological variation patterns within populations. Many algorithms have been established to reduce variation introduced into vocalic data from physiological sources. The lack of real-time studies tracking the effectiveness of these normalization algorithms from childhood through adolescence inhibits exploration of child participation in vowel shifts. This analysis compares normalization techniques applied to data collected from ten African American children across five time points. Linear regressions compare the reduction in variation attributable to age and gender for each speaker for the vowels BEET, BAT, BOT, BUT, and BOAR. A normalization technique is successful if it maintains variation attributable to a reference sociolinguistic variable, while reducing variation attributable to age. Results indicate that normalization techniques which rely on both a measure of central tendency and range of the vowel space perform best at reducing variation attributable to age, although some variation attributable to age persists after normalization for some sections of the vowel space.

1.
Adank
,
P.
(
2003
). “
Vowel normalization: A perceptual-acoustic study of Dutch vowels
,” Ph.D. thesis,
University of Nijmegen
, pp.
1
198
.
2.
Adank
,
P.
,
Smits
,
R.
, and
van Hout
,
R.
(
2004
). “
A comparison of vowel normalization procedures for language variation research
,”
J. Acoust. Soc. Am.
116
,
3099
3107
.
3.
Ainsworth
,
W. A.
(
1975
). “
Intrinsic and extrinsic factors in vowel judgments
,” in
Auditory Analysis and Perception of Speech
, edited by
G.
Fant
and
M. A. A.
Tatham
(
Academic
,
London
) pp.
103
113
.
4.
Bailey
,
G.
, and
Thomas
,
E. R.
(
1998
). “
Some aspects of African-American Vernacular English phonology
,” in
African-American English
, edited by
S. S.
Mufwene
,
J. R.
Rickford
,
G.
Bailey
, and
J.
Baugh
(
Routledge
,
London
), pp.
85
109
.
5.
Bennett
,
S.
(
1981
). “
Vowel formant frequency characteristics of preadolescent males and females
,”
J. Acoust. Soc. Am.
69
,
231
238
.
6.
Bennett
,
S.
(
1983
). “
A 3-year longitudinal study of school-aged children’s fundamental frequencies
,”
J. Speech Hear. Res.
26
,
137
142
.
7.
Boersma
,
P.
, and
Weenink
,
D.
(
2010
). “
Praat: Doing phonetics by computer (version 5.1.34) [computer program]
,” http://fon.hum.uva.nl/praat/ (Last viewed February 1, 2012).
8.
Clopper
,
C.
(
2009
). “
Computational methods for normalization acoustic vowel data for talker differences
,”
Lang. Ling. Compass
3
,
1430
1442
.
9.
Disner
,
S.
(
1980
). “
Evaluation of vowel normalization procedures
,”
J. Acoust. Soc. Am.
67
,
253
261
.
10.
Eckert
,
P.
(
1997
). “
Age as a sociolinguistic variable
,” in
The Handbook of Sociolinguistics
, edited by
F.
Coulmas
(
Blackwell
,
Oxford
), pp.
151
167
.
11.
Eguchi
,
S.
, and
Hirsch
,
I. J.
(
1969
). “
Development of speech sounds in children
,”
Acta Oto-Laryngol.
257
,
1
51
.
12.
Fabricius
,
A. H.
,
Watt
,
D.
, and
Johnson
,
D. E.
(
2009
). “
A comparison of three speaker-intrinsic vowel formant frequency normalization algorithms for sociophonetics
,”
Lang. Var. Change
21
,
413
435
.
13.
Fant
,
G.
(
1975
). “
Non-uniform vowel normalization
,” Speech Transmission Laboratory Quarterly Progress and Status Report No. 2–3 (Royal Institute of Technology, Stockholm), pp.
1
19
.
14.
Fitch
,
W. T.
, and
Giedd
,
J.
(
1999
). “
Morphology and development of the human vocal tract: A study using magnetic resonance imaging
,”
J. Acoust. Soc. Am.
106
,
1511
1122
.
15.
Flynn
,
N.
(
2011
). “
Comparing vowel formant normalisation procedures
,”
York Pap. Linguist., Ser. 2
11
,
1
28
.
16.
Gerstman
,
L.
(
1968
). “
Classification of self-normalized vowels
,”
IEEE Trans. Audio Electroacoust.
AU-16
,
78
80
.
17.
Hindle
,
D.
(
1978
). “
Approaches to vowel normalization in the study of natural speech
,” in
Linguistic Variation: Models and Methods
, edited by
D.
Sankoff
(
Academic
,
New York
), pp.
161
171
.
18.
Kerswill
,
P.
(
1996
). “
Children, adolescents, and language change: The state of the art
,”
Lang. Var. Change
8
,
177
202
.
19.
Labov
,
W.
(
2001
).
Principles of Linguistic Change. Vol. II: Social Factors
(
Blackwell
,
Oxford
), pp.
157
164
.
20.
Lee
,
S.
, and
Iverson
,
G.
(
2009
). “
Vowel development in English and Korean: Similarities and differences in linguistic and non-linguistic factors
,”
Speech Commun.
51
,
684
694
.
21.
Lobanov
,
B. M.
(
1971
). “
Classification of Russian vowels spoken by different listeners
,”
J. Acoust. Soc. Am.
49
,
606
608
.
22.
Miller
,
J. D.
(
1989
). “
Auditory-perceptual interpretation of the vowel
,”
J. Acoust. Soc. Am.
85
,
2114
2134
.
23.
Nearey
,
T. M.
(
1978
). “
Phonetic feature systems for vowels
” (
Indiana University Linguistics Club
,
Indiana
), pp.
1
200
.
24.
Nearey
,
T. M.
(
1989
). “
Static, dynamic, and relational properties in vowel perception
,”
J. Acoust. Soc. Am.
85
,
2088
2113
.
25.
Nearey
,
T. M.
(
1992
). “
Applications of generalized linear modeling to vowel data
,” in
Proceedings of the 1992 International Conference on Spoken Language Processing
, Banff, Alberta, Canada, October 13–16, 1992, pp.
583
587
.
26.
Nordström
,
P. E.
, and
Lindblom
,
B.
(
1975
). “
A normalization procedure for vowel formant data
,” in
Proceedings of the 8th International Congress of Phonetic Sciences
, August 1975, Leeds, p.
212
.
27.
Peterson
,
G. E.
, and
Barney
,
H. L.
(
1952
). “
Control methods used in a study of the vowels
,”
J. Acoust. Soc. Am.
24
,
175
184
.
28.
Roberts
,
J.
(
1997
). “
Hitting a moving target: Acquisition of sound change in progress by Philadelphia children
,”
Lang. Var. Change
9
,
249
266
.
29.
Rosner
,
B. S.
, and
Pickering
,
J. B.
(
1994
).
Vowel Perception and Production
(
Oxford University Press
,
Oxford
), pp.
214
265
.
30.
Syrdal
,
A. K.
(
1984
). “
Aspects of a model of the auditory representation of American English vowels
,”
Speech Commun.
4
,
121
135
.
31.
Syrdal
,
A. K.
, and
Gopal
,
H. S.
(
1986
). “
A perceptual model of vowel recognition based on the auditory representation of American English vowels
,”
J. Acoust. Soc. Am.
79
,
1086
1100
.
32.
Thomas
,
E. R.
(
2002
). “
Instrumental phonetics
,” in
The Handbook of Language Variation and Change
, edited by
J. K.
Chambers
,
P.
Trudgill
, and
N.
Schilling-Estes
(
Blackwell
,
Oxford
), pp.
168
200
.
33.
Thomas
,
E. R.
(
2011
).
Sociophonetics: An Introduction
(
Palgrave Macmillan
,
Basingstoke, UK
), pp.
160
171
.
34.
Thomas
,
E. R.
, and
Kendall
,
T.
(
2007
). “
NORM: The vowel normalization and plotting suite
,” http://ncslaap.lib.ncsu.edu/tools/norm/ (Last viewed August 16, 2011).
35.
Traunmüller
,
H.
(
1990
). “
Analytical expressions for the tonotopic sensory scale
,”
J. Acoust. Soc. Am.
88
,
97
100
.
36.
Van Hofwegen
,
J.
, and
Wolfram
,
W.
(
2010
). “
Coming of age in African American English: A longitudinal study
,”
J. Sociolinguist.
14
,
427
455
.
37.
Vorperian
,
H. K.
, and
Kent
,
R. D.
(
2007
). “
Vowel acoustic space development in children: A synthesis of acoustic and anatomic data
,”
J. Speech Lang. Hear. Res.
50
,
1510
1545
.
38.
Watt
,
D.
, and
Fabricius
,
A.
(
2002
). “
Evaluation of a technique for improving the mapping of multiple speakers’ vowel spaces in the F1–F2 plane
,”
Leeds Work. Pap. Linguist. Phonetics
9
,
159
173
.
39.
Whiteside
,
S.
(
2001
). “
Sex-specific fundamental and formant frequency patterns in a cross-sectional study
,”
J. Acoust. Soc. Am.
110
,
464
478
.
40.
Whiteside
,
S. P.
,
Hodgson
,
C.
, and
Tapster
,
C.
(
2002
). “
Vocal characteristics in pre-adolescent and adolescent children: A longitudinal study
,”
Logoped. Phoniatr. Vocol.
27
,
12
20
.
41.
Yaeger-Dror
,
M.
, and
Thomas
,
E. R.
, eds. (
2010
).
African American English Speakers and Their Participation in Local Sound Changes: A Comparative Study
(
Duke University Press
,
Durham, NC
), pp.
9
10
.
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