Copyright © 2003 by K. Stromswold
Lab 3: Speech
Perception 2: Voice Onset Time
(VOT)
In this lab you
will listen to examples of 7 synthetically produced speech syllables. These syllables are CV syllables
comprised of a bilabial stop consonant followed by the vowel [a]. The syllables are generated so they
differ only in voice onset time (VOT) (i.e., the amount of type that
elapses between the initial burst and the onset of voicing). VOTs for the 7 types of syllables range
from 0 msec to 60 msecs.
Practice
Trials. We will first listen to each of the 7 syllables played in sequential
order, starting with 0 msec VOT and ending with a 60 msec VOT. For each of the syllables, indicate
whether you perceive a [ba] or [pa].
1. ba pa
2. ba pa
3. ba pa
4. ba pa
5. ba pa
6. ba pa
7. ba pa
Identification
Trials. You will now listen to 35 syllables presented in random order. For each of the syllables, indicate
whether you perceive a [ba] or [pa].
1. ba pa
22. ba pa
2. ba pa 23. ba pa
3. ba pa
24. ba pa
4. ba pa
25. ba pa
5. ba pa
26. ba pa
6. ba pa
27. ba pa
7. ba pa
28. ba pa
8. ba pa
29. ba pa
9. ba pa
30. ba pa
10. ba pa
31. ba pa
11. ba pa
32. ba pa
12. ba pa
33. ba pa
13. ba pa
34. ba pa
14. ba pa
35. ba pa
15. ba pa
16. ba pa
17. ba pa
18. ba pa
19. ba pa
20 ba pa
21. ba pa
Part 1. Overall class data
A. At the end of this handout, you will
find the VOT values for each of the 35 syllables. Using this information and the individual data for all of
your classmates, fill out the following chart for the overall class data (i.e.,
combine all of your classmates' data)
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Stimulus VOT |
1 |
2 |
3 |
4 |
5 |
Total 'ba' |
Total 'pa' |
%ba |
%pa |
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60 |
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B. Are there
any trials that appear to be aberrant?
If so, what could account for this?
C. Make a line graph and put the overall
data for the class on the graph.
Clearly label the line that corresponds to the overall class data. You may graph your results by hand on
graph paper or you may use a computer graphing program (e.g., Excel).
D. Where is the categorical boundary for
the class as a whole?
Part 2. Data for native speakers of English
A. Fill out the following chart for class
data for students who are native speakers of English.
|
Stimulus VOT |
1 |
2 |
3 |
4 |
5 |
Total 'ba' |
Total 'pa' |
%ba |
%pa |
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0 |
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10 |
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60 |
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B. Are there
any trials that appear to be abberant?
If so, what could account for this?
C. Add a line corresponding to the native
English speakers' data on the graph made above. Make sure you label it.
D. Where is the categorical boundary for
the native English speakers? Is
the categorical boundary 'sharper' for native English speakers than for the
class as a whole? If so, why might
this be?
Part 3. Data for nonnative speakers of English
A. Fill out the following chart for class
data for students who are NOT native English speakers.
|
Stimulus VOT |
1 |
2 |
3 |
4 |
5 |
Total 'ba' |
Total 'pa' |
%ba |
%pa |
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0 |
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10 |
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60 |
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B. Are there
any trials that appear to be aberrant?
If so, what could account for this?
C. Add a line corresponding to the
nonnative English speakers' data to the graph. Make sure you label it.
D. Where is the categorical boundary for
the nonnative English speakers? Is
the categorical boundary for nonnative English speakers different from that of
native English speakers? If so,
why might this be?
Part 4. Your data
A. Fill out the following chart for your
own individual data.
|
Stimulus VOT |