Wedel, A. B. (2007). Feedback and regularity in the lexicon. Phonology, 24:147–185.
[online at Google scholar]

This paper shows how simple simulations can model phonologic phenomena as emergent from the dynamics of a rich memory model. Using an exemplar-based model of the lexicon, Wedel discusses two sets of simulations.

One shows how cross-linguistic patterns of allophony can be seen as different attractors in a dynamic system. Like how some languages only use apical /l/, some only use velar /l/, and some use both in different contexts, random production or perception error and articulatory or perceptual markedness preferences, along with similarity bias resulting from analogical error over the variety of contexts in the lexicon produces three metastable states, corresponding to the three kinds of patterns witnessed in natural languages. Furthermore, this series of simulations shows how strict dominance in OT is often true, but can nevertheless sometimes be violated. The model predicts that strict dominance is violated when a majority of examples in the lexicon have the constraints in conflict, whereas strict dominance does hold true when constraints conflict less often in the lexicon.

The second simulation shows how word stress patterns can emerge from a similar interaction of kinds of error, driven by the distribution of features in the lexicon. The simulation is set up with a bias toward alternating stress and a bias toward vowel+sonorant as the minimum heavy rhyme. The interaction of these constraints in the lexicon gives two different patterns, depending on how large a portion of syllables in the lexicon have vowel+sonorant rhymes. If the number is small, the alternating stress bias dominates, and the stress pattern becomes consistently alternating, basically ignoring the heavy syllable constraint. However, if the number is large, the pattern is generalized as any vowel+consonant is heavy also, because the [+sonorant] feature together with half the [+consonantal] that are in alternating syllables looks like a [+cons] constraint. This is the pattern observed in the languages of the world, that CVV = heavy is common, and CVV+CVC = heavy is common, but CVV + CV[+son] = heavy is rare.

These studies provide a new perspective into the causes underlying phonological patterns. This model apparently currently lacks an analytic formulation, but the general patterns exhibited here suggest that a more phonetically-driven, dynamical model of phonology promises a better understanding of how phonological patterns arise.

Ussishkin, A., Twist, A., and Velan, H. (2007). Lexical organization in Semitic: Psycholinguistic evidence from Modern Hebrew and Maltese. Distributed by email.

This paper describes two studies that begin a research program to investigate the psychological validity of consonantal root vs whole word theories of Semitic morphology. The traditional analysis of Semitic verbal and nominal morphology states that each lemma class is based on a single consonantal root, such that each word form is produced by the combination of the consonantal root with a syllabic (vowel & consonant) affix, into a bare (C*V*)* template. However, other analyses have proposed that words might be accessed as whole words. (And that the template merely reflects historical word formation processes.) For example, a previous proposal by Ussishkin theorized that the word forms in a semantically-related lemma class are all derived from a single base form, with overriding infixes.

There are two experiments described here, one in Hebrew and one in Maltese. The basic experimental paradigm is that of lexical decision. Whereas previous related research has typically used visual presentation of stimuli, in these studies the stimuli were presented auditorily. Since the orthography of Semitic languages typically gives preferential status to consonants, orthographic presentation of stimuli creates a potential confound. The primary stimuli were words and pseudo-words created using two common conjugation patterns (called binyanim for Hebrew, themes for Maltese). The consonants were also common roots, so that the pseudo-words were incidentally unattested forms rather than morphologically illicit.

In both studies, the frequency effect was not properly controlled, in the first study because of an error in the design (Ussishkin, personal communication — but didn’t elaborate), and in Maltese because there was no corpus available at that time. The results of these studies are difficult to interpret, but with a later study (presented in person) they support the theory that both the consonantal root and the whole word are stored in long term memory. The facilitatory effect of word form frequency as well as the facilitatory effect of morphological family size (the number of word forms in a lemma class) indicate that information about whole words is stored in memory, but little or no delay for more complex forms and the organization into lemma classes, as well as other studies, make it clear that the consonantal root does have strong psychological validity.