Modelling the perceptual development of first- and second-language phonological contrasts with the Gradual Learning Algorithm Paola Escudero, University of Reading Paul Boersma, University of Amsterdam Amsterdam, February 22, 2001
Sound Contrasts Sound contrasts and acoustic information An example of a sound contrast in English What are the acoustic differences between the two?
Acoustic cues to “ship” vs. “sheep”
Elspeth’s production environment (Scottish English)
Liz’s production environment (Southern English)
Elspeth and Liz’s production environments, averaged
Do Elspeth and Liz perceive [350 Hz, 80 ms] as “ship” or as “sheep”?
Why using the nearest production prototype in perception? Why not perceiving it as an /e/ or an /o/? Answer: “ likelihood maximisation ”, the most likely category Functional principle: minimise the probability of perceptual confusion
How do Elspeth and Liz perceive the segments reliably? [350 Hz, 80 ms] 350 Hz not /I/ 80 ms not /i/ 80 ms not /I/ 350 Hz not /i/ /I/*!* /i/ ** [350 Hz, 80 ms] 350 Hz not /i/ 80 ms not /i/ 80 ms not /I/ 350 Hz not /I/ /I/ ** /i/*!* E L
How about baby Elspeth and baby Liz?
Little Elspeth makes a mistake when categorising [350 Hz, 80 ms] [350 Hz, 80 ms] 350 Hz not /i/ 80 ms not /i/ 80 ms not /I/ 350 Hz not /I/ /I/ ** ** /i/*! **
Little Elspeth and little Liz learn to perceive “ship” and “sheep” reliably
The perception of real adult Elspeth and Liz
How about adult Isabel and adult Carmen that move to Scotland and Southern England, respectively? Do they learn to perceive English “ship” and “sheep”? If so, how do they do it?
Isabel and Carmen’s production environment (Spanish)
Isabel and Carmen’s perception (Spanish)
New production environment (English) Scotland
How Isabel learns to perceive “ship” and “sheep” (1) Scotland
How Isabel learns to perceive “ship” and “sheep” (2) Scotland
How Isabel learns to perceive “ship” and “sheep” (3) Scotland
How Isabel learns to perceive “ship” and “sheep” (4) Scotland
How Isabel learns to perceive “ship” and “sheep” (5) Scotland
How Isabel learns to perceive “ship” and “sheep” (6) Scotland
The perception of real Isabel
South England New production environment (English)
How Carmen learns to perceive “ship” and “sheep” (1) South England
How Carmen learns to perceive “ship” and “sheep” (2) South England
How Carmen learns to perceive “ship” and “sheep” (3) South England
How Carmen learns to perceive “ship” and “sheep” (4) South England
How Carmen learns to perceive “ship” and “sheep” (5) South England
How Carmen learns to perceive “ship” and “sheep” (6) South England
The perception of real Carmen (1)
BUT...! The perception of real Carmen (2)
L1 and L2 categorisation: Elspeth vs. Isabel
L1 and L2 categorisation: Liz vs. Carmen
Summary For our perception model, we assumed: 1) OT perception grammar with GLA 2) Grammar copying (full transfer for L2) 3) Category duplication With these assumptions, we can handle: 1) L1 Scottish and Southern English 2) L2 Scottish and Southern English, partially
BUT!! We could not completely handle L2 English!! Solution?: ‘Cues categorised separately’, the L2 grammar consists of the following constraints instead 1)“350 Hz not /mid/”, “350 Hz not /high/” 2)“80 ms not /short/”, “80 ms not /long/”
Conclusion Cue reliance depends on cue reliability, or: Differences in production account for differences 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.
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