Upload
emily-berry
View
216
Download
0
Embed Size (px)
Citation preview
The Role of Phonological Distance and Relative Support on the Productivity of the Dutch Simple Past Tense
Bram Vandekerckhove, Emmanuel Keuleers, & Dominiek SandraCenter for PsycholinguisticsUniversity 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
V suffix
wilf -edpast
4
How do we inflect novel forms?
• Similarity-based single-mechanism models- Regular and irregular inflection:
• Analogy-based productivity
wilf => ?
will => wouldkill => killed
fill => filleddelve => delved
5
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
6
Prasada & Pinker 1993, stimuli
• Type: distance from irregular/regular verbs• Distances: Prototypical/Intermediate/Distant• Pattern: Vowel change/suffix
Pseudo-irregular verbs Pseudo-regular verbs
Proto. Interm. Dist. Proto. Interm. Dist.
spling fring trisp plip brilth frilg
splungsplinged
frungfringed
trusptrisped
plupplipped
brulthbrilthed
frulgfrilged
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
spring cling
stingswing
11
Memory-Based Modelling
wilf
willfill
killfill
12
Prasada & Pinker 1993: back to the stimuli
Pseudo-irregular verbs Pseudo-regular verbs
Proto. Interm. Dist. Proto. Interm. Dist.
spling fring trisp plip brilth frilg
splungsplinged
frungfringed
trusptrisped
plupplipped
brulthbrilthed
frulgfrilged
irr: 5.4 irr: 3.3 irr: 0 irr:0 irr:0 irr:0
reg:6.2 reg: 4.5 reg: 2.4 reg: 7.2 reg:0 reg: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.
Label N (1434) Exemplars
---də 770 (0.537) hoor-hoorde, bel-belde, ruim-ruimde
---tə 339 (0.236) gap-gapte, lok-lokte, gulp-gulpte, wik-wikte
---ə 145 (0.101) laad-laadde, schud-schudde, raad-raadde
-eː- 45 (0.031) prijs-prees, slijt-sleet, grijp-greep
-ɔ- 38 (0.026) zend-zond, zink-zonk, zing-zong, tref-trof
-oː- 32 (0.022) scheer-schoor, vlied-vlood, luik-look
-iː- 16 (0.011) help-hielp, was-wies, slaap-sliep, loop-liep
-ɑ- 14 (0.010) treed-trad, eet-at, vreet-vrat, lees-las
-uː- 7 (0.005) jaag-joeg, zweer-zwoer, vaar-voer
-ɔxt 4 (0.003) koop-kocht, dunk-docht, zoek-zocht
-ɑxt 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)
18
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, 54-65.):- k nearest neighbors = the whole lexicon- Exemplars are weighted by an exponential decay
function
An alternative explanation
k1 k7 k1 k1k7 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.