The Role of Phonological Distance and Relative Support on the Productivity of the Dutch Simple Past Tense

Bram Vandekerckhove, Emmanuel Keuleers, & Dominiek Sandra Center for Psycholinguistics University of Antwerp

Wilf ing

on the web, the new British pastime

Wilf t

u wel eens?

Maar liefst zeven op de tien mensen erkennen dat ze wel eens

'wilf en ’

dus dan moet er

ge wilf t

worden

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How do we inflect novel forms?

3 • Dual-Mechanism Model - Regular inflection: • Governed by rules that operate over abstract symbols • Fully productive • Default V - Irregular inflection: • Database of stored word forms • Limited productivity • Similarity-based analogies • Blocks the default V wilf suffix -ed past

How do we inflect novel forms?

4 • Similarity-based single-mechanism models - Regular and irregular inflection: • Analogy-based productivity kill => killed fill => filled will => would wilf => ?

delve => delved

Prasada & Pinker 1993

• S. Prasada & S. Pinker (1993). Generalisation of Regular and Irregular Morphological Patterns. Language and Cognitive Processes 8, 1-56.

• Past tense acceptability ratings • Rate on a scale from 1 to 7 - Today, I spling, yesterday I splinged - Today, I spling, yesterday I splung - Today, I plip, yesterday I plipped - Today, I plip, yesterday I plup 5

Prasada & Pinker 1993, stimuli

6 • Type: distance from irregular/regular verbs • Distances: Prototypical/Intermediate/Distant • Pattern: Vowel change/suffix Pseudo-irregular verbs Proto.

spling

Interm.

fring

Dist.

trisp splung splinged frung fringed trusp trisped

Pseudo-regular verbs Proto.

plip

Interm.

brilth

Dist.

frilg plup plipped brulth brilthed frulg frilged

Prasada & Pinker 1993: Predictions

7 • Dual-Mechanism Model - Irregular inflection: • Negative effect of Phonological Distance from existing irregular verbs - Regular inflection: • No effect of Phonological Distance from existing regular verbs • Analogy-based models - Regular and irregular inflection: • According to Prasada & Pinker (1993) (!): Effect of Phonological Distance from existing regular and irregular verbs

Prasada & Pinker 1993: results

8

However ...

9 Is a similarity-based model really bound to fail in strong dissimilarity conditions?

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Memory-Based Modelling

spring cling swing spling sting

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Memory-Based Modelling

fill will wilf fill kill

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Prasada & Pinker 1993: back to the stimuli

Pseudo-irregular verbs Pseudo-regular verbs Proto.

spling

Interm.

fring

Dist.

trisp

Proto.

plip

Interm.

brilth

Dist.

frilg

Keuleers & Sandra (submitted). Similarity and Productivity in the English Past Tense.

14

Implications

• Findings of Prasada & Pinker can be explained as the result of Relative Support effects in a k nn model.

• The question whether Phonological Distance from existing verbs in itself has a negative effect on regular/irregular productivity is still unresolved.

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A new experiment

• Investigation of the effects of Phonological Distance and Relative Support on the productivity of regular and irregular patterns of the Dutch simple past tense.

iː ɑ uː ɔxt ɑxt ...

Label -- də -- tə -- ə eː ɔ oː N (1434) Exemplars 770 (0.537) hoor-hoorde, bel-belde, ruim-ruimde 339 (0.236) gap-gapte, lok-lokte, gulp-gulpte, wik-wikte 145 (0.101) laad-laadde, schud-schudde, raad-raadde 45 (0.031) prijs-prees, slijt-sleet, grijp-greep 38 (0.026) zend-zond, zink-zonk, zing-zong, tref-trof 32 (0.022) scheer-schoor, vlied-vlood, luik-look 16 (0.011) help-hielp, was-wies, slaap-sliep, loop-liep 14 (0.010) treed-trad, eet-at, vreet-vrat, lees-las 7 (0.005) jaag-joeg, zweer-zwoer, vaar-voer 4 (0.003) koop-kocht, dunk-docht, zoek-zocht 2 (0.001) breng-bracht, denk-dacht

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Method

• Past tense acceptability rating task • Stimuli selected on the basis of the output of a memory-based simulation, with model trained on monomorphemic verbs (CELEX): - Phonological Distance of the nearest neighbor - Relative Support for one of 6 past tense classes (3 regular allomorphs, 3 largest vowel-change classes)

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Predictions

• Dual-Mechanism Model - Regular inflection • No effect of Phonological Distance • Possible postive effect of Relative Support (partial blocking) - Irregular inflection • Negative effect of Phonological Distance • Positive effect of Relative Support • K-nn model - Regular and irregular inflection • Positive effect of Relative Support • No effect of Phonological Distance

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Results plot

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Results and Discussion

• Positive effect of Relative Support on mean ratings for both regular and irregular forms • Negative effect of Phonological Distance on mean ratings for irregular forms • No significant effect of Phonological Distance on mean ratings for regular forms

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Results and discussion

• Regular inflection - Both models make the correct predictions.

- Preference for k-nn model.

• Irregular inflection - K-nn model makes the wrong prediction.

- Preference for Dual-Mechanism Model?

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An alternative explanation

• K-nn model is a rather crude implementation of the memory-based approach to cognitive/linguistic modelling. • Generalized Context Model: ( Nosofsky, R. M. (1988). Similarity, frequency and category representations.

Journal of Experimental Psychology: Learning, Memory and Cognition

, 14, 54-65.

) : - k nearest neighbors = the whole lexicon - Exemplars are weighted by an exponential decay function

An alternative explanation

k1 k7 k1 k7 k1 k7

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An alternative explanation

• In the k-nn model, irregular nearest neighbors that had a relatively high Phonological Distance from the test item might have been too influential in comparison with items that were somewhat further away • We have not yet explored this possibility.

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Conclusions

• A k-nn model is very good model of regular productivity.

• At the moment, a dual-mechanism model seems to account best for the productivity of the Dutch simple past tense.

• However, a more sophisticated implementation of the memory-based approach might be a better model for this pattern of results.