Proceedings, FONETIK 2005, Department of Linguistics, Göteborg University
Tonal word accents produced by Swedish 18- and 24month-olds
Germund Kadin and Olle Engstrand
Department of Linguistics, Stockholm University
accent contrast and that, in consequence, Swedish word accent acquisition typically takes
place during the 18-24 months age interval. In
the present study, this assumption was tested
using a group of 18-month-olds. To verify the
language-specificity of observed accent patterns, comparable groups of American English
18- and 24-month-olds were used as controls.
Abstract
F0 measurements were made of disyllabic
words produced by several Swedish and American English 18- and 24-month-olds. The Swedish 24- and 18-monthers produced accent contours that were similar in shape and timing to
those found in adult speech. The Swedish 18monthers, however, produced very few words
with the acute accent. It is concluded that most
Swedish children have acquired a productive
command of the word accent contrast by 24
years of age and that, at 18 months, most children display clear tonal ambient-language effects. The influence of the ambient language is
evident in view of the F0 contours produced by
the American English children whose timing of
F0 events tended to be intermediate between the
Swedish grave and acute contours. The relative
consistency with which grave accent contours
were produced by the Swedish 18-monthers
suggest that some children are influenced by
the ambient language well before that age.
Methods
Subjects were drawn from a larger group of approximately 60 Swedish and 60 American English children at the ages of 6, 12, 18, 24 and 30
months. Audio and video recordings were made
as described in Engstrand et al. (2003). The
present study is based on recordings of
• 11 Swedish 24-month-olds (6 girls, 5 boys)
• 13 American 24-month-olds (6 girls, 7
boys)
• 11 Swedish 18-month-olds (6 girls, 5 boys)
• 16 American 18-month-olds (9 girls, 7
boys),
i.e., a total of 51 children, including the 24monthers used in Engstrand and Kadin (2004).
All disyllabic words with stress on the first syllable were analyzed according to criteria described in Engstrand and Kadin (2004). F0 was
measured at five points in time: at 1) the acoustic onset of V1, 2) the F0 turning-point in V1 (if
the F0 contour was monotonic throughout the
vowel, the turning-point was assigned the value
of the onset), 3) the acoustic offset of V1, 4) the
acoustic onset of V2, and 5) maximum F0 in V2
(if F0 declined throughout the vowel, maximum
F0 was assigned the value of the onset). A Fall
parameter was defined as the F0 difference between V1 turning-point and offset, and a Rise
parameter was defined as the F0 difference between V2 maximum and V1 offset. All measurements were made using the Wavesurfer program package.
Introduction
Swedish has a contrast between a ‘grave’ and
an ‘acute’ tonal word accent. The acute accent
is associated with a simple, one-peaked F0 contour. The grave accent typically has a twopeaked F0 contour with a fall on the primary
stress syllable and a subsequent rise towards a
later syllable in the word (Bruce 1977, Engstrand 1995, 1997).
A preliminary report on Swedish children’s
acquisition of the word accents was presented
in Engstrand and Kadin (2004). The results,
which were based on 6 Swedish and 6 American English 24-month-olds, suggested that, at
that age, Swedish children are well on the way
to establishing a productive command of the
accent contrast. The present study was carried
out to test this preliminary conclusion using
additional subjects. In addition, previous studies (Engstrand et al. 1991, Engstrand et al.
2003) have suggested that most 17-18-montholds display a much less consistent use of the
Results
Auditory judgments first suggested that a majority of the words produced by the Swedish
children (both 18- and 24-month-olds) had a
grave-like tonal contour and that, in general,
67
Proceedings, FONETIK 2005, Department of Linguistics, Göteborg University
grave and acute accents were assigned to
words in accordance with the adult norm. In
contrast, none of the American English word
productions sounded convincingly grave.
this fall was, on the whole, less marked than for
the older group (the grand means were 76 and
50 Hz for the 24- and 18-monthers, respectively). The Rise parameter, too, was positively evaluated for most 18-monthers but,
again, less consistently than for the 24monthers (grand means 111 and 55 Hz, respectively). Two of the 18-monthers (SW18F3 and
SW18M5) did not evidence any rise into the
second vowel.
Measurement results are summarized in table 1-5 (a full statistical treatment will be reported elsewhere). The tables present means
and standard deviations for the Fall and Rise
parameters. The bottom line of each table
shows grand means and standard deviations. In
the left column, SW and AM represent Swedish
and American English, respectively, 18 and 24
indicate the respective ages in months, and F
and M stand for sex (female or male). The last
figure is a reference number that identifies the
individual child. Thus, for example, SW24F1
stands for a Swedish 24 months old girl with
the reference number 1.
Table 2. Means for the Fall and Rise parameters in
grave accent words produced by the Swedish 18monthers.
Child
SW18F1
SW18F2
SW18F3
SW18F4
SW18F5
SW18F6
SW18M1
SW18M2
SW18M3
SW18M4
SW18M5
Grand
mean
Table 1. Means for the Fall and Rise parameters in
grave accent words produced by the Swedish 24monthers.
Child
SW24F1
SW24F2
SW24F3
SW24F4
SW24F5
SW24F6
SW24M1
SW24M2
SW24M3
SW24M4
SW24M5
Grand
mean
GRAVE ACCENT
Fall (Hz)
Rise (Hz)
Mean SD Mean SD
69
62
102 121
60
29
69
40
62
45
70
66
113
88
93 129
72
41
99 124
77
38
127 125
102 141
392 286
59
42
70
84
101 122
106 136
70
59
42
78
60
35
50
44
76
64
111
112
N
21
22
19
26
23
12
2
23
23
21
23
GRAVE ACCENT
Fall (Hz)
Rise (Hz)
Mean SD Mean SD
41 44
139 180
59 41
94
67
30 28
1,0
65
64 17
33
24
114 107
52 219
27 18
70
98
43 46
58
85
23 38
45
44
39 33
38 134
35 29
83
34
80 93
-3,0
27
50
45
55
89
N
2
14
4
4
7
2
17
4
6
13
2
75
The Swedish acute productions were relatively
few – 37 in all produced by 6 of the 11 24month-olds. Thus, 5 of the Swedish 24monthers lacked acute productions altogether
(table 3). Again, the Fall parameter had positive
values which were, however, smaller than in
the grave productions (and, as we shall see,
with a different timing of the F0 peaks). The
Rise parameter values differ markedly from
those pertaining to the grave words in that they
were consistently negative. This means that the
acute words displayed a continuous F0 decline
from an early peak in the first syllable. In other
words, the acute words had a clearly ‘onepeaked’ F0 contour.
215
Swedish grave words produced by the 24month-olds consistently displayed positive values for both the Fall and the Rise parameters
(table 1). This means that 1) F0 declined from a
turning-point in the primary stress vowel reaching a relatively low value at the end of that
vowel, and 2) rose to resume a relatively high
position in the second vowel resulting in a
‘two-peaked’ F0 contour.
Acute productions by the Swedish 18monthers were too few to provide a basis for
reliable generalizations. However, parameter
values tended to differ from those for the grave
productions and to resemble those pertaining to
the 24-monthers.
The Swedish 18-month-olds show a similar,
but somewhat less consistently two-peaked
contour (table 2). The positive values of the
Fall parameter indicate that F0 declined from a
turning-point in the primary stress vowel, but
68
Proceedings, FONETIK 2005, Department of Linguistics, Göteborg University
Table 5. Means for the Fall and Rise parameters in
words produced by the American 18-monthers.
Table 3. Means for the Fall and Rise parameters in
acute accent words produced by the Swedish 24monthers.
Child
SW24F1
SW24F2
SW24F3
SW24F4
SW24F5
SW24F6
SW24M1
SW24M2
SW24M3
SW24M4
SW24M5
Grand mean
ACUTE ACCENT
Fall (Hz)
Rise (Hz)
Mean SD Mean SD
29 11
46 78
96 49
11 2,0
42 9,5
-3,7 25
-79 106
-29 22
-52 1,7
16
2,7
35
31
-73
57
43
15
-37
27
AMERICAN ENGLISH
Fall (Hz)
Rise (Hz)
Mean SD Mean SD N
AM18F1
41 68
-47 67 5
AM18F2
19 27
84 171 6
AM18F3
0
-11
1
AM18F4
39 49
-33 190 10
AM18F5
30
52
1
AM18F6
27 24
-48 102 12
AM18F7
28 22
-27 18 4
AM18M1
11
159
1
AM18M2
36 36
24 73 8
AM18M3
36 25
25 83 10
AM18M4
44 78
4,8 79 5
Grand mean
28 41
17 98 63
Child
N
0
6
7
3
9
0
0
7
0
5
0
37
The above tables have shown differences between accent types and ambient languages in
terms of the Fall and Rise parameters. Thus,
timing has so far been disregarded. However,
timing of F0 events in relation to segmental
structure is crucial as illustrated in figure 1. The
figure shows mean data for the Swedish and
American English children in both age groups
(symbols are explained in the figure legend).
Grave and acute productions are shown for the
Swedish 24-monthers. F0 values are timealigned to the first measurement point, and the
data points are connected by smoothed lines
that bear a certain resemblance to authentic F0
contours. The measurement points correspond
to acoustic events as described above.
F0 values pertaining to the American children
tended to resemble those for the Swedish acute
productions (see tables 4 and 5; five of the 16
American 18-monthers did not produce any usable utterances and have been left out). The
Fall parameter values were moderately positive
and the Rise parameters tended to be on the
negative side. Thus, the American data suggest
a moderate F0 decline in the first vowel which,
on average, continued into the second vowel.
Table 4. Means for the Fall and Rise parameters in
words produced by the American 24-monthers.
AMERICAN ENGLISH
Child
Fall (Hz)
Rise (Hz)
Mean SD Mean SD N
AM24F1
69 82
-53 175 12
AM24F2
58 41
-4,5 45 16
AM24F3
33 23
-2,8 57 13
AM24F4
55 71
-80 81 15
AM24F5
32 31
-28 57 13
AM24F6
51 24
-2,9 76
7
AM24M1
20 27
-6,4 58 16
AM24M2
50 75
5,6 27 16
AM24M3
29 36
-40 82 16
AM24M4
93 149 -0,71 90
7
AM24M5
26 21
31 45 10
AM24M6
27 26
2,6 47
9
AM24M7
34
17
1
Grand mean
45 51
-10 70 151
The main timing effect is found in the first
F0 maximum which, for the Swedish children,
appears early in the stressed vowel of the grave
words and near the following vowel-consonant
boundary in the acute words. The productions
pertaining to American children are intermediate with an F0 maximum approximately at or
after the middle of the stressed syllabe. Also
note the differences in the second vowel (mesurement points 4 and 5). The contour describes
a steady slope in the Swedish acute productions, whereas the grave contour reaches as
new peak in the second vowel. Thus, the acute
contour differs from the grave contour both in
having a late turning-point in the first vowel
and in lacking a secondary peak in the following vowel. Even though the American English
contours reflect occasional rises toward the
69
Proceedings, FONETIK 2005, Department of Linguistics, Göteborg University
second vowel, these rises are smaller and less
systematic than those of the Swedish grave
contours.
months, many Swedish children begin to produce grave-like F0 contours and to mark the appropriate words with these contours. Engstrand
et al. (2003) reached a similar conclusion on
the basis of listening tests. Based on those studies as well as preliminary analyses of the present material, Engstrand and Kadin (2004) hypothesized that acquisition of the Swedish tonal
word accents typically takes place in the 18-24
months age interval. However, the relative consistency with which grave accent contours were
produced by the present 18-monthers would
suggest that some children are influenced by
the ambient language well before this age. This
is in agreement with results of listening tests
suggesting occasional grave-like tone contours
as early as at 12 months of age (Engstrand et al.
2003).
Time (ms)
Figure 1. Average F0 contours derived from mean
parameter values shown in tables 1 - 5. Symbols:
filled diamonds=SW24 grave, unfilled diamonds=SW18 grave, gray diamonds=SW24 acute,
filled squares=AM24, unfilled squares=AM18.
Acknowledgment
Summary and conclusions
This work was supported by grant 2003-846014311-29 from the Swedish Research Council
(VR) to O. Engstrand.
Auditory judgments have shown that disyllabic
words produced by Swedish 24- and 18-montholds mainly carry the grave tonal word accent.
This is an expected influence of the ambient
language, since a majority of disyllabic Swedish words are characterized by that accent.
Whereas the Swedish 24-monthers also produced a significant number of acute words, the
acute accent occurred very rarely in the
younger group. F0 contours were usually
shaped and timed according to the adult norm.
This was the case in all 24-month-olds and in
all but two of the 18-month-olds. This suggests
that most Swedish children at 24 months of age
have established a productive command of the
word accent contrast, and that many 18-montholds are in a fair way to acquiring the grave accent. However, the virtual absence of acute
words in the 18-month-olds makes it hard to
determine whether a systematic accent contrast
has been established at that age.
References
Bruce G. (1977) Swedish Word Accents in
Sentence Perspective. Lund: Gleerup.
Engstrand O. (1995) Phonetic interpretation of
the word accent contrast in Swedish. Phonetica 52, 171-179.
Engstrand O. (1997) Phonetic interpretation of
the word accent contrast in Swedish: Evidence from spontaneous speech. Phonetica
54, 61-75.
Engstrand O., Williams K. and Strömqvist S.
(1991) Acquisition of the tonal word accent
contrast, Actes du XIIème Congres International des Science Phonétiques, Aix-enProvence, vol. 1, pp. 324-327.
Engstrand O., Williams K. and Lacerda F.
(2003) Does babbling sound native? Listener
responses to vocalizations produced by
Swedish and American 12- and 18-montholds. Phonetica 60, 17-44.
Engstrand O. and Kadin G. (2004) F0 contours
produced by Swedish and American 24month-olds: implications for the acquisition
of tonal word accents. Proceedings of the
Swedish Phonetics Conference held in Stockholm 26-28 May 2004, pp. 68-71.
The influence of the ambient language is
even more evident in view of the F0 contours
produced by the American English controls.
The timing of those contours tended to be intermediate between the Swedish grave and
acute contours.
Out of the five Swedish 17-18-month-olds
observed in a similar study (Engstrand et al.
1991), three showed a two-peaked, grave-like
F0 contour in grave words (even though a rise
was consistently present on the second syllable). It was tentatively concluded that, at 17
70