<OT> New Posting: ROA-913

[roa at ruccs.rutgers.edu]

ROA 913-0507

Implementing Escudero's model for the SUBSET problem

Klara Weiand <kweiand at science.uva.nl>

Direct link: http://roa.rutgers.edu/view.php3?roa=913


Abstract:
This paper reports on the results of a series of experiments
that put Escudero's theoretical model to a practical test.
This model was developed to explain how Dutch learners of
Spanish vowels solve the SUBSET problem. Escudero’s model
uses Stochastic Optimality Theory and, in this paper, we
use this same framework with the Gradual Learning Algorithm
to simulate learning on the basis of Escudero’s proposal.

Escudero's model is based on empirical data which shows
that Dutch learners initially use three native categories
to classify the two Spanish vowels /i/ and /e/. The model
proposes that this initial situation leads to non-optimal
perception as well as non-optimal recognition because three
words instead of two will be stored in this learner’s L2
lexicon. The empirical data also shows that advanced learners
can attain optimal L2 perception. To explain this L2 development,
the model proposes that both perceptual learning and lexical
feedback are involved in the reduction of one of the three
native categories to acquire optimal L2 sound perception
and word recognition.


The proposal for the initial state in Dutch learners of
Spanish vowels relies on the existence of minimal pairs
in Spanish which
are assumed to lead to the storage of lexical entries different
in form but identical in meaning and entries identical in
form but different in meaning. Escudero proposes that the
existence of two entries with the same form but with different
meanings leads to what she calls semantic errors. The proposal
also says that, when the learner notices these errors through
contextual cues, perceptual learning will occur, just like
in the lexicon-driven learning proposed in Boersma for L1
acquisition and in Escudero and Boersma for L2 acquisition.


In order to computationally test Escudero's proposal, several
different parameter settings and correct candidate selection
mechanisms were compared. It was found that the model as
proposed in principle is viable but is very sensitive to
noise. A different selection mechanism and alternate rankings
remedy this problem, leading to complete category elimination
and boundary shifts to the native positions.

Comments: 
Keywords: perception, learning, categorization, second language, Spanish, Dutch, simulation
Areas: Phonology,Phonetics,Learnability,Psycholinguistics,Language Acquisition
Type: Manuscript

Direct link: http://roa.rutgers.edu/view.php3?roa=913