modelling the perceptual development of phonological contrasts with ot and the gla paola escudero...
Post on 21-Dec-2015
212 views
TRANSCRIPT
Modelling the perceptual developmentof phonological contrasts with
OT and the GLA
Paola [email protected]
Paul [email protected]
Utrecht Institute of Linguistics May 14 2001
Introduction The Language Acquisition task The task in Phonological Acquisition
– Mapping from acoustic input to discrete categories– E.g.
Overview of the talk– /I/ vs. /i/ in two English varieties– Modelling perception and its acquisition– Comparison with real listeners
Elspeth’s production environment(Scottish English)
260
300
400
50050 60 90 120 150 180
Duration (ms)
Liz’s production environment(Southern English)
260
300
400
50050 60 90 120
Duration (ms)
Elspeth’s and Liz’saverage production environments
260
300
400
50050 60 90 120
Duration (ms)
/I/
/i//I/
/i/
Do Elspeth and Liz perceive [349 Hz, 74 ms] as “ship” or as “sheep”?
260
300
350
400
450
50050 60 80 100 120
Duration (ms)
?
/I/
/i//I/
/i/
Why does perception have to depend on the production environment?
Answer: to optimise perception, the listener has to
minimise the probability ofperceptual confusion
The optimal perception strategy, therefore, is:
likelihood maximisation, i.e.choose the most likely produced category,given a certain F1 & duration
Maximum likelihood strategy
260
300
400
50050 60 90 120
/i/?
/I/
Duration (ms)
260
300
400
50050 60 90 120
/i/
/I/ ?
Duration (ms)
The knowledge underlying Elspeth’s and Liz’ optimal perception
[349 Hz,
74 ms]
349 Hz
not //74 ms
not //74 ms
not //349 Hz
not // // *! *
// * *
[349 Hz,
74 ms]
349 Hz
not //74 ms
not //74 ms
not //349 Hz
not // // * *
//
*! *
Initial stage of babies Elspeth and Liz
260300
400
50050 70 90 120
dur.rel. 0.7%
How is the knowledge acquired?
Answer: Little Elspeth learns by
applying the GLA whenever she
makes a categorisation error
[349 Hz,
74 ms]
349 Hz
not //74 ms
not //74 ms
not //349 Hz
not //
// * *
// *! *
How little Elspeth learns to perceive“ship” and “sheep” reliably (1)
260300
400
50050 70 90 120
dur.rel. 0.5%1 month
How little Elspeth learns to perceive“ship” and “sheep” reliably (2)
260300
400
50050 70 90 120
dur.rel. 9.6%2 months
How little Elspeth learns to perceive“ship” and “sheep” reliably (3)
260300
400
50050 70 90 120
dur.rel. 13.8%4 months
How little Elspeth learns to perceive“ship” and “sheep” reliably (4)
260300
400
50050 70 90 120
dur.rel. 11.2%10 months
How little Elspeth learns to perceive“ship” and “sheep” reliably (5)
260300
400
50050 70 90 120
dur.rel. 4.5%100 months
How little Elspeth learns to perceive“ship” and “sheep” reliably (6)
260300
400
50050 70 90 120
dur.rel. 8.4%1000 months
How little Liz learns to perceive “ship” and “sheep” reliably (1)
260300
400
50050 70 90 120
dur.rel. 57.9%1 month
How little Liz learns to perceive “ship” and “sheep” reliably (2)
260300
400
50050 70 90 120
dur.rel. 76.6%2 months
How little Liz learns to perceive “ship” and “sheep” reliably (3)
260300
400
50050 70 90 120
dur.rel. 48.3%4 months
How little Liz learns to perceive “ship” and “sheep” reliably (4)
260300
400
50050 70 90 120
dur.rel. 57.7%10 months
How little Liz learns to perceive “ship” and “sheep” reliably (5)
260300
400
50050 70 90 120
dur.rel. 74.2%100 months
How little Liz learns to perceive “ship” and “sheep” reliably (6)
260300
400
50050 70 90 120
dur.rel. 68.2%1000 months
Real vs. Simulated listeners
260300
400
50050 70 90 120
dur.rel. 8.4%260300
400
50050 70 90 120
dur.rel. 68.2%
Scottishdur.rel. 10.6%
83 177480
344
Southerndur.rel. 34.6%
83 177480
344
What about L1-Spanish Isabel, who moves to Scotland and then
to Southern England?
Isabel’s production environment (Spanish)
260
300
350
400
450
50050 60 80 100 120
Duration (ms)
/i/
/e/
Isabel’s adult perception (Spanish)
260300
400
50050 70 90 120
dur.rel. -0.8%200 months
Isabel’s new production environment (Scottish English)
I FA
260
300
350
400
450
50050 60 80 100 120
Duration (ms)
/I/
/i/
How Isabel learns to perceive“ship” and “sheep”
260300
400
50050 70 90 120
dur.rel. 9.2%300 months
Isabel’s new production environment (Southern English)
260
300
350
400
450
50050 60 80 100 120
Duration (ms)
/I/
/i/
How Isabel learns to perceive“ship” and “sheep”
260300
400
50050 70 90 120
dur.rel. 64.8%400 months
Three types of real L2 categorisation
Spectral reliance only Duration reliance onlyCue integration
mfdur.rel. -5.7%
83 177480
344
mtdur.rel. -10.0%
83 177480
344
abgdur.rel. 40.0%
83 177480
344
efdur.rel. 85.7%
83 177480
344
ofdur.rel. 98.6%
83 177480
344
ljdur.rel. 70.0%
83 177480
344
Summary
For our perception model, we assumed:
1) Perception is handled by an OT grammar
2) Its acquisition is handled by the GLA
3) L2 learners start by copying their L1 grammar
With these assumptions, we can model:
1) L1 Scottish and Southern English
2) L2 Scottish and Southern English, partially
Conclusion Cue reliance depends on cue reliability, or
a) Differences in the production environment account for differences in perception.
b) Changes in the production environment lead to changes in perception.
The functional principle underlying this production-perception dependence is “minimisation of perceptual confusion”.
This functional principle follows from our formal modelling of the perception grammar.
Thank you for your attention!