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)

scorreia@ualg.pt

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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