Previous notes
This talk was presented at GALA 2007, Barcelona;
Slide 8 was added afterwards;
Slides 27 and 29 were added for PDF visualization purposes;
SAMPA phonetic transcription was used for technical reasons (PC/MAC compatibility);
Sound files are not available - if needed, please contact the author;
I wish to thank to the audience for the relevant comments.
Acoustic correlates of stress in early disyllabic productions of
2 Portuguese childrenSusana Correia
ESSaF (Univ. Algarve) Onset-CEL (Univ. Lisboa)
GALA 2007, UAB, Barcelona
Studies on the acquisition of stress
Non acoustic studies with production data:
Neutral hypothesis:
English - Hochberg, 1988;
Trochaic bias:
Dutch - Fikkert, 1994;
English - Allen & Hawkins, 1980; Demuth & Fee, 1995;
Iambic bias:
English and French - Vihman et al., 1998 (iambic phrases)
Brazilian Portuguese - Santos, 2001, 2005
Previous works on Portuguese (Santos, 2001, 2005; Correia et al., 2006) have shown an iambic tendency, although, again, no acoustic analysis had been taken;
Many cases of level stress were also found in the data:
Inês 1;3.6 - Papa /’pap6/ - [papa] (with sound file)
Inês 1;3.6 - Tapa /’tap6/ - [pap6] (with sound file)
Joana 1;9.25 - (Ri)cardo /Ri’kardu/ - [kaka] (with sound file)
Joana 1;9.25 - Papa /’pap6/ - [papa] (with sound file)
Acoustic-based studies with production data (Pollock et
al., 1993 - English; Kehoe et al., 1995 - English; Lintfert & Schndeider, 2006 -
German; Lleó & Arias, 2007 - German/Spanish):
Until about 1;8-2;0, children are not able to control the acoustic parameters to mark stress according to the target;
Perception data with infants (Echols, 1996; Johnson & Jusczyk,
2001; Nazzi & Ramus, 2003; , Vihman et al., 2004):
Infants are able to discriminate stressed from unstressed vowels/syllables and to distinguish stressed from mistressed words in the language they are exposed to;
Segmental structure in the stressed syllable can be easily retrieved in infants perception but it may depend on language-specific properties.
Primary word stress in EP
Lexical contrast:
[S’plisitu] ‘explicit’ ≠
[Spli’situ] ‘I make explicit’ ≠
[Splisi’to] ‘s/he made explicit’
Not duration/weight sensitive (Pereira, 1999, among others);
Unstressed vowels are frequently reduced or deleted:
bato ‘I beat’ [‘batu]~[‘batw]
bate ‘s/he beats’ [‘bat@]~[‘bat]
Word stress in EP is not stored in the lexicon and it has to be learnt by means of an algorithm (morphological information, Pereira, 1999);
Several authors have stated that EP has a predominant trochaic rhythmic pattern (Pereira, 1999).
Indeed, words in EP are predominantly stressed in the penult syllable IF we disregard monossylables (31.46%).
If monossylables are taken into account and if we consider them to be stressed word-finally, final stress pattern is reinforced in the language (Frota, Vigário & Martins, 2006).
Stress position (monossyl. included)
0%
20%
40%
60%
80%
100%
Final Penult Antepenult
Stress position (monossyl. excluded)
0%
20%
40%
60%
80%
100%
Final Penul Antepenult Monossyll.
Some arguments can be provided to account for the fact that monossylables can be added to the syllable-final stressed words in EP:
Stressed monossylables (not clitic ones) have the same syllable structure as final stressed syllables of polissyllabic words (nasality, diphthongization, nasality and diphthongization and CVC syllables):
cães [‘k6~j~S]‘dogs’ - alemães [6l@’m@~j~S] ‘germans’
pão [‘p6~w~]‘bread’ - canção [k6~’s6~w~] ‘song’
pás ‘shovels’, paz ‘peace’ - rapaz ‘boy’
EP is a proclitic language (97% of clitic words are proclitic - Vigário, Martins & Frota, 2006) - many monossyllabic words are preceded by phonological clitics, thus forming a wS PW;
‘...a mão...’ [6’m6~w~] ‘the hand’, ‘...o dá...’ [u’da] ‘give it’, ‘...lhe faz...’ [L@’faS] ‘does him’
added
Acoustic cues for word stress in EP
Delgado-Martins (1988):
Sets of 3 similar words (e.g. Spl’isitu, Splis’itu, Splisit’o) not showing intermediate vowel reduction; each word was said in a sentence context (‘say ______ again’).
Stress parameters measured: F0, duration, intensity and energy.
‘Duration and energy mark the stress in the final and the antepenult syllable.’
‘F0 and intensity do not cue word stress’.
‘The stressed vowel in word of type 2 - with stress in the penultimate syllable - does not present any regular stress index.’
Research questions
Is there a significant acoustic difference between the first and the second vowel (V1 and V2) in the first 2-syllable productions in the observed children?
If there is any, in what direction (trochaic, iambic)?
Acquisition of word stress during phonological acquisition:
If no difference is found between V1 and V2, one might predict that children are not processing an hierarchical relation between both vowels;
If a difference is found between V1 and V2, one might predict that children’s productions show evidence for an hierarchical relation between both vowels;
If a difference is to be found, one might find empirical evidence for a trochaic or iambic bias in Portuguese children’s early speech and across early development.
Effect of target properties (EP) in children’s productions:
If a difference is not found, the relation between language properties and/or input frequencies and children’s early productions has to be discussed;
If children are sensitive to the adult/target grammar, one might expect these children to correspond to the rhythmic/stress patterns of the target language.
Method
Longitudinal data from spontaneous speech of 2 Portuguese monolingual children, observed in a monthly basis;
Inês - 0;11.14 - 1;3.6 (4 sessions);
Joana - 0:11.24 - 2;0.9 (11 sessions);
The data were transcribed in Phon database (Rose et al., 2006) and judged by 2 persons;
For acoustic analysis, only disyllabic productions (Inês: 86/782, Joana: 79/1287) were considered;
Simultaneous speech/noise, unintelligible productions and reduplicated forms (≥ 3 syll.) were not analyzed;
Acoustic parameters measured using Praat software - F0 (stable point/middle), intensity (peak), duration and energy (mean) - V1 vs. V2;
CDS sample - 1 session per child (1 hour) at the same age (around 1;3)
frequencies extracted with FreP software (PTDC/LIN/70367/2006 - www.fl.ul.pt/LaboratorioFonetica/freP)
Joana’s CDS - 2488 PWs; Inês’ CDS - 4355 PWs.
For statistical analysis SPSS 11.0 for Macintosh was used.
Method
!=V2!=V1
The data - acoustic parameters standardization
F0
Duration
Intensity
Energy
Standardized values for acoustic parameters:
vi-MeanAcPar(per session)
SDAcPar (per session)
Non-parametric Wilcoxon signed-rank test
!=V1 !=V2
Statistics
Find ONE global, relational value for each V
Inês - V1 Inês - V2 Joana - V1 Joana - V2
With sound files
Results
The data distribution
Frequency of selected target stress patterns
Stress position (words W/ + 2 syll.))
57.20%63.60%
42.70%36.30%
0%
20%
40%
60%
80%
100%
Inês Joana
PenultLast
InêsF0
Intensity
Duration
Energy
8585N =F0V2F0V1
800
600
400
200
08585N =
Intensi tyV2Intensi tyV1
90
80
70
60
50
40
8585N =DurationV2DurationV1
.6
.5
.4
.3
.2
.1
0.0
1
59
12
16
8585N =EnergyV2EnergyV1
.03
.02
.01
0.00
-.01
29357936132254552018
221
19
28697529801820
13
1983221
2255
Joana
7979N =
V2 F0V1 F0
1000
0
112
F0
7979N =
V2 DurationV1 Duration
,8
,6
,4
,2
0,0
-,2
12
47
16323428
Duration
7979N =
V2 IntensityV1 Intensity
90
80
70
60
50
3933413
Intensity
7979N =
V2 EnergyV1 Energy
,01
0,00
-,01
3674
39
1
47
3126774
52
5
Energy
InêsTarget iambs Target trochees
JoanaTarget iambs Target trochees
Results - Inês - Target iambs
Data suggest that, until session 4 (1;3.6), the difference between V1 and V2 is NOT statistically SIGNIFICANT (p<,05) in iambic target words.
Iambs: V1 Mdn = -,72 vs. V2 Mdn = -,30, T = -1,1, p = ,115
4949N =
TSTREPAT= Iamb
V2V1
4
3
2
1
0
-1
-2
1
5
2
44
Results - Inês - Target trocheesUntil session 3 (1;1.30), in target trochees, a SIGNIFICANT difference bewteen V1 and V2 is observed. Against expected, V2 was produced with significant HIGHER values than V1:
Trochees: V1 Mdn = -,39 vs. V2 Mdn = ,05; T = ,00, p = ,01
66N =
TSTREPAT= Troch
V2V1
2,5
2,0
1,5
1,0
,5
0,0
-,5
-1,0
51
By this time, filler sounds are very frequent:
- mamã ‘mummy’ /m6’m6~/ -> [a’ma] (1;0.25- toma ‘take it’ /t’Om6/ -> [a’dO] (1;0.25)- chupeta ‘pacifier’ /Sup’et6/ -> [6’be] (1;1.30)
Later, Inês often truncates target trissylables into iambic dissyllables (Vigário, Freitas & Frota, 2006):
- boneca ‘doll’ [bun’Ek6] -> [meJ’E] (1;5.11)- laranja ‘orange’ [l6r6~Z6] - > [lal’a] (1;5.11)- queijinho ‘cheese dim.’ [k6jZ’iJu] - > [kEk’i] (1;6.6)
Results - Inês - Target trocheesWith session 4 (1;3.6), in target trochees, a significant difference between V1 and V2 is NOT OBSERVED, as in target trochees V1 is starting to be produced with higher values:
Trochees: V1 Mdn = -1,06 vs. V2 Mdn = -1,38; T = -1,4, p = ,074
1717N =
TARSTREP= 1.00
V2V1
10
0
-10
13
1
13
2
Data suggest that there is NO SIGNIFICANT DIFFERENCE between V1 and V2 until session 9 (1;9.25), both for iambic and for trochaic target words (in accordance with previous works - Vigário, Freitas & Frota, 2006 and Correia, Costa & Freitas, 2006)
Iambs: V1 Mdn = -1,03 vs. V2 Mdn = -,96; T=50, p = ,105
Trochees: V1 Mdn = -,96 vs. V2 Mdn = -,51; T =9; p = ,199
Target iambs Target trochees
Results - Joana - Target trochees and target iambs
1717N =
TSTREPAT= Iamb
V2V1
20
10
0
-10
1
4
3
77N =
TSTREPAT= Troch
V2V1
3
2
1
0
-1
-2
-3
59
59
Results - Joana - Target trochees and target iambs
In sessions 10 and 11, a SIGNIFICANT DIFFERENCE was found between V1 and V2, both in target iambs and trochees (p<,05).
Iambs: V1 Mdn = -1,25 vs. V2 Mdn = ,57; T = 33, p = ,000
Trochees: V1 Mdn = -,27 vs. V2 Mdn = -,76; T = 152, p = ,039
Joana was able to assign prominence according to the target (iambs: V1<V2; trochees: V1>V2).
3535N =
TSTREPAT= Iamb
V2V1
8
6
4
2
0
-2
-4
34
27
2020N =
TSTREPAT= Troch
V2V1
12
10
8
6
4
2
0
-2
-4
6272
62
Stress position (monossyl. included)
0%
20%
40%
60%
80%
100%
Final Penult Antepenult
Discussion - Inês Inês’ data suggest that for iambic target words there is no
difference between V1 and V2 at an initial stage (until 1;3.6);
For trochaic target words, a significant difference was found until 1;1.30: she seems not to master the prominence in trochaic target words, preferring the iambic words:
High percentage of target iambs selected for the first productions;
Iambs’ formation through fillers insertion;
Iambic bias
Expressive evidence for final stress in CDS and in
the adult grammar?[cf. next slide for CDS graph]
CDS - Inês (monossyll.=final stress)
0%
20%
40%
60%
80%
100%
Final Penult Antepenult
Stress position (monossyl. included)
0%
20%
40%
60%
80%
100%
Final Penult Antepenult
Joana’s data suggest that until 1;9.25 there is no difference between V1 and V2 in her dissyllabic productions;
Discussion - Joana
Neutral hypothesis
Higher values associated to V2 (duration) (even if the difference is not statistically significant);
High percentage of target iambs selected for the first productions;
Iambic bias
Previous works on Portuguese (Santos 2001) suggested that in their early productions, Brazilian speaking children could be dealing with accent, rather than word stress
[cf. next slide for CDS graph]
CDS - Joana (monosyll.=final stress)
0%
20%
40%
60%
80%
100%
Final Penult Antepenult
Discussion
Why can Portuguese children not show an initial trochaic bias?
Target frequencies: EP shows good evidence for final stress;
CDS frequencies: EP CDS tends to include many words like ‘bebé’, ‘mamã’, ‘papá, ‘aqui’, ‘ali’, ‘cocó’, ‘chichi’ (all iambs) and monossylables .
Vowel reduction in EP: many trochees surface as iambs.
The two children show different behavior towards stress:
Inês’ data seem to point to an iambic bias;
Joana’s data do not show a clear tendency for a particular stress pattern, but target iambs are preferred and the second vowel is generally more prominent than the first one in her early productions.
The children observed seem to be sensitive both to the adult grammar and to the input frequency:
Inês seems to be more sensitive to the CDS but a larger sample of CDS must be transcribed and analyzed in order to verify this hypothesis;
Joana’s productions seem to mirror the balance of the target language and the CDS.
No evidence for the ‘universal trochaic bias’
Final remarks
Thank you!Research integrated in the research unit Onset-CEL
POCTI-SFA-17-745
Research funded by the PhD national fellowshipSFRH/BD/21696/2005
FreP tool developed within the projectPTDC/LIN/70367/2006
www.fl.ul.pt/LaboratorioFonetica/FreP
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