An Investigation of the Effect of Multiple Productions on the Single Word Production of People with

Acquired Speech Sound Production Difficulties: An Analysis of 2 Cases

Lynn Li Lim1,2, Karen Croot1,2,3, Sallyanne Palethorpe1,2, Max Coltheart1,2

1. Macquarie Centre for Cognitive Science (MACCS), Macquarie University

2. Speech Hearing and Language Research Centre (SHLRC), Macquarie University

3. School of Psychology, The University of Sydney

Acoustic Analysis Speech disorders may share similar

symptoms of impaired speech production To determine the speech disorder associated

with the symptom examine speech segment productions acoustically

Gives more concrete information on speech qualities attributed to phonological & articulatory deficits

More reliable than impressionistic phonetic transcription (Haley et al, 2001)

Acoustic Speech Analysis Most common acoustic investigations are on

contrastive features to determine if speech segment errors are:

Phonemic – substitution of one phoneme for another

Phonetic – impaired articulation of a speech sound(Baum et al, 1990; Tuller, 1984)

Variability in Speech Production Unimpaired speech production can be

somewhat variable (Auzou et al, 2000)

Acoustic studies usually rely on multiple productions of speech tokens to overcome this variability

People with speech disorders are far more variable in their productions than controls (Ryalls, 1986)

But disordered speech analyses have not addressed the issue of possible effects of multiple productions

And their results have been inconsistent

Multiple Production Not known if eliciting multiple word

productions from these people affects their speech sound production difficulties

H1: Fatigue – deterioration of speech production

H2: Practice – improvement in speech production

H0: No effect on speech production

Previous Studies Some examples for Vowel Duration

Study: Ryalls (1986) Tuller (1984) Williams & Seaver (1986)

Speakers 5 N/FL

7 FL

5 N/FL

5 FL

7 N/FL

14 FL

Repetitions per word

5 16 1

Mean Durations

N/FL & FL > CTRL N/FL & FL > CTRL 2 N/FL > Others

Variability N/FL > FL & CTRL N/FL & FL > CTRL(Only some)

N/FL & FL < CTRL

Multiple Production

Implication: If there are effects, then method of eliciting

speech tokens may confound the investigation of the nature of the disorder

Other Features of Speech Production Previous acoustic studies address question

of whether speakers produce phonemic or phonetic errors

Other information about speech production difficulties that are non-contrastive in nature

These are not usually reported in most acoustic studies

Research Questions

Q1: Does multiple repetition of target words affect phonetic parameters of the speech of people with impaired speech sound production?

Q2: Are there other phonetic parameters in the speech of these individuals that might be indicative of the nature of the disorder but not usually reported?

Speakers

AR 63 y.o., male progressive aphasia with other mild cognitive

deficits 2.5 years after presentation impaired syntax & phoneme discrimination semantic abilities just below control range moderate hearing loss

(35-50 dB loss at 4kHz, 55-70 dB loss at 6 kHz)

Speakers

HO 62 y.o., male left middle cerebral artery infarct early 1996 unimpaired visuo-perceptual processing of

pictures & words semantic abilities just below control range impaired receptive phonological processing moderate hearing loss

(45-55 dB loss at & above 4 kHz)

Material

Experiment 1 Experiment 2Words 15 12

Repetitions (per session) 6 15

Sessions 5 5

* Words were presented in pseudo-random order among fillers

Task Reading Reading

Words used in current study

bed, big, dark, duck,pen, pig, pick, saw, sea

buck, bug

puck, pad, pat

Speaker(s) AR, HO HO

Recordings digitised at 20,000 Hz

Spectrograms hand-labelled & analysed using the EMU speech database system & the R statistical analysis software

Acoustic dimensions analysed: Burst Release Duration (BRDUR) Vowel Duration (VDUR) Fricative Spectral Moments (FSM)

First SM (SM1): average spectral frequency

Acoustic Procedure

Q1: Statistical Analysis Repeated Measures ANOVA To investigate for any significant differences

in the variance between sessions

Sphericity: assumption that variance is equal between pairs of scores(Field, 2000, p.324)

Q1: Results - Error-bar Plots

Example: Burst Release Duration of /d/ (AR)

A B C D E

session

-50.00

0.00

50.00

100.00

150.00

brd

ur

A B C D E

session

-50.00

0.00

50.00

100.00

150.00

brd

ur

dark duck

Q1: Results - Error-bar Plots

Example: Burst Release Duration of /p/ (HO)

pen

A B C D E

session

-50.00

0.00

50.00

100.00

150.00

brd

ur

pig

A B C D E

session

-50.00

0.00

50.00

100.00

150.00

brd

ur

pick

A B C D E

session

-50.00

0.00

50.00

100.00

150.00

brd

ur

Q1: Results - Error-bar Plots

Example: 1st Spectral Moment of /s/ (HO)

A B C D E

session

4000.00

5000.00

6000.00

7000.00

sm1

A B C D E

session

4000.00

5000.00

6000.00

7000.00

sm1

saw sea

Q1: Results - Error-bar Plots

Example: Vowel Duration of /I/ (AR)

big

1 2 3 4 5

session

100.00

150.00

200.00

250.00

vdu

r

pig

1 2 3 4 5

session

100.00

150.00

200.00

250.00

vdu

r

pick

1 2 3 4 5

session

100.00

150.00

200.00

250.00

vdu

r

Vowel duration /I/ in “Big” (Speaker AR)Descriptive Statistics

Mean Std. Deviation N

SESSION1 177.2333 25.69425 6

SESSION2 187.5333 31.51582 6

SESSION3 135.0167 20.12912 6

SESSION4 133.6800 25.64429 6

SESSION5 161.9833 21.51803 6

Mauchly's Test of Sphericity

Within Subjects Effect Mauchly's W Approx. Chi-Square df Sig.

Speaker AR (Big - VDUR) .013 14.954 9 .127

Tests of Within-Subjects Effects

Source Sum of Squares df Mean Square F Sig.

Speaker AR (Big – VDUR) 14230.612 4 3557.653 6.798 .001

Error 10466.874 20 523.344

Q1: Results - ANOVA

Pairwise Comparisons

Measure: MEASURE_1

-10.300 10.444 1.000 -60.152 39.552

42.217 8.926 .052 -.391 84.825

43.553 16.581 .467 -35.595 122.702

15.250 7.388 .939 -20.015 50.515

10.300 10.444 1.000 -39.552 60.152

52.517* 6.042 .003 23.678 81.355

53.853 21.075 .509 -46.745 154.452

25.550 15.055 1.000 -46.313 97.413

-42.217 8.926 .052 -84.825 .391

-52.517* 6.042 .003 -81.355 -23.678

1.337 16.299 1.000 -76.466 79.140

-26.967 11.116 .597 -80.026 26.093

-43.553 16.581 .467 -122.702 35.595

-53.853 21.075 .509 -154.452 46.745

-1.337 16.299 1.000 -79.140 76.466

-28.303 11.387 .555 -82.656 26.049

-15.250 7.388 .939 -50.515 20.015

-25.550 15.055 1.000 -97.413 46.313

26.967 11.116 .597 -26.093 80.026

28.303 11.387 .555 -26.049 82.656

(J) SESSION2

3

4

5

1

3

4

5

1

2

4

5

1

2

3

5

1

2

3

4

(I) SESSION1

2

3

4

5

MeanDifference

(I-J) Std. Error Sig.a

Lower Bound Upper Bound

95% Confidence Interval forDifference

a

The mean difference is significant at the .05 level.*.

Adjustment for multiple comparisons: Bonferroni.a.

Q1: Results - ANOVA

Q1: Summary of Results ANOVA: significant differences between

sessions for only some words Post-hoc: significant differences between

session means were few and no pattern of increase/decrease in

differences across sessions Results were similar for VDUR, BRDUR,

Fricative SM1, the other words, both speakers

Results were also similar in 2nd experiment

Q1: Summary of Results No change across sessions = no effect

(practice/fatigue) of multiple productions

Also, no. of repetitions in Exp 2 > Exp 1, yet no effect of increased repetition on speech production

Implication of Results method of eliciting multiple production may

not confound investigation of nature of speech disorder

but for treatment – practice of this type elicited in this study may not contribute to improvement in speech production

Q2: Other Speech Production Features Pre-voicing (HO)

Pre-voicing

Example: BugFigure 1a Figure 1b

Q2: Other Speech Production Features Pre-voicing (HO)

– voicing preceding release

of word initial /b/ & /d/

Impaired laryngeal control

– difficulty coordinating

timing of stop release for

voiced stops

Word Occurrence

Bed 83%

Big 52%

Buck 95%

Bug 89%

Dark 52%

Duck 63%

Q2: Other Speech Production Features Schwa

appended to final stop (HO)

Example: Pad

Schwa

Figure 3

Q2: Other Speech Production Features Schwa appended to word-final stop (HO)

– Voiced stops

Indicative of careful

speech production Or due to speech

disorder Or due to hearing loss

Word Occurrence

/d/ in “Bed” 93%

/d/ in “Pad” 44%

/g/ in “Big” 86%

/g/ in “Bug” 77%

/g/ in “Pig” 53%

No pattern in occurrence of these features over sessions

Not an effect of multiple production May just be characteristic of disordered

speech production

Q2: Other Speech Production Features - Summary

Future Directions Word-final consonants (stops) Nasal consonants Co-articulation Analysis of the other speech production

features Analysis of control data

Thank you for listening