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

2 Wilfing on the web, the new British pastime Wilft u wel eens? Maar liefst zeven op de tien mensen erkennen dat ze wel eens 'wilfen’ dus dan moet er gewilft worden

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

4 How do we inflect novel forms? Similarity-based single-mechanism models -Regular and irregular inflection: Analogy-based productivity wilf => ? will => wouldkill => killed fill => filled delve => delved

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

6 Prasada & Pinker 1993, stimuli Type: distance from irregular/regular verbs Distances: Prototypical/Intermediate/Distant Pattern: Vowel change/suffix Pseudo-irregular verbsPseudo-regular verbs Proto.Interm.Dist.Proto.Interm.Dist. splingfringtrispplipbrilthfrilg splung splinged frung fringed trusp trisped plup plipped brulth brilthed frulg frilged

7 Prasada & Pinker 1993: Predictions 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

8 Prasada & Pinker 1993: results

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

10 Memory-Based Modelling spling springcling sting swing

11 Memory-Based Modelling wilf will fill kill fill

12 Prasada & Pinker 1993: back to the stimuli Pseudo-irregular verbsPseudo-regular verbs Proto.Interm.Dist.Proto.Interm.Dist. splingfringtrispplipbrilthfrilg splung splinged frung fringed trusp trisped plup plipped brulth brilthed frulg frilged irr: 5.4irr: 3.3irr: 0 reg:6.2reg: 4.5reg: 2.4reg: 7.2reg:0

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.

15 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.

LabelN (1434)Exemplars ---də770 (0.537) hoor-hoorde, bel-belde, ruim-ruimde ---tə339 (0.236)gap-gapte, lok-lokte, gulp-gulpte, wik-wikte ---ə145 (0.101)laad-laadde, schud-schudde, raad-raadde -e ː - 45 (0.031)prijs-prees, slijt-sleet, grijp-greep -ɔ--ɔ- 38 (0.026)zend-zond, zink-zonk, zing-zong, tref-trof -o ː - 32 (0.022)scheer-schoor, vlied-vlood, luik-look -i ː - 16 (0.011)help-hielp, was-wies, slaap-sliep, loop-liep -ɑ--ɑ- 14 (0.010)treed-trad, eet-at, vreet-vrat, lees-las -u ː - 7 (0.005)jaag-joeg, zweer-zwoer, vaar-voer - ɔ xt 4 (0.003)koop-kocht, dunk-docht, zoek-zocht - ɑ xt 2 (0.001)breng-bracht, denk-dacht...

17 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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19 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

20 Results plot

21 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

22 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?

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

An alternative explanation k1k7k1 k7

25 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.

26 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.