- 1:00 Welcome by Mike Hammond
- Introductory remarks by Andy Wedel
Friday, April 25, 2008: Harvill rm. 115
- 1:15 - 2:15 Harry Tily
- Diachronic processing preferences and their implications for models of syntactic change
- 2:15 – 3:15 Neal Snider
- An exemplar model of syntactic production
Tea Break
- 3:30 – 4:30 Joan Bresnan
- Predicting Syntax: Processing Dative Constructions in Two Varieties of English
- 4:30 – 5:30 Discussion
Dinner at Poca Cosa
- 8:30 Coffee
Saturday, April 26, 2008: Harvill rm. 102
- 8:45 – 9:45 Rob Malouf, Farrell Ackerman and Jim Blevins
- Inflectional morphology as a complex adaptive system
- 9:45 – 10:45 Melissa Redford
- Meaning and Mechanics in Speech and Language Acquisition
Tea Break
- 11:00 – 12:00 Eduardo Altmann
- Recurrences in processes with long-term memory
Lunch
- 1:30—2:30 Robert Daland
- Language variation: convergence, divergence and death
- 2:30 – 3:30 Colin Dawson
- 'Second-Order Learning' as a Source of Structure Stabilization in Both Individual Learning and Cultural Evolution
Tea Break
- 3:45 – 4:45 Andy Wedel
- Modeling sublexical contrast maintenance as an emergent effect of lexical category competition
- 4:45 – 5:45 Clay Beckner and Andy Wedel
- Modeling contributions of usage versus acquisition to language change
Department Potluck party at 7 at Adam Ussishkin and Andy Wedel’s house
Modeling contributions of usage versus acquisition to language change
Clay Beckner and Andy Wedel
Traditional attempts to identify a root cause for language change have pitted language acquisition against language usage, assuming that innovation is traceable either to imperfect intergenerational learning, or to cognitive and social processes among adults (Jespersen 1922). This particular dichotomy may obscure the dynamics of change more than it enlightens (e.g., Hopper & Traugott 2003). Instead, a more useful distinction may lie between change at the category label level versus changes in mappings from category label to content. Acquisition and usage differ in the pre-existence of established percept-category mappings: in the process of language acquisition, a new system of category labels is progressively abstracted from primary data, while in usage, the mapping between category labels and percept types is employed to organize incoming data.
A wide range of evidence indicates that mappings between category labels and percepts can change with experience, allowing the character of a category to slowly shift over time (reviewed in Pierrehumbert 2001, Bybee 2002). However, there is also a good deal of evidence that the pre-existing pattern of categorial distinctions influences the way that information is perceived and stored. In particular, information tends to be processed in a way that is consistent with and reinforces the existing set of categories (e.g., Ganong 1980, Nosofsky 1988; see also work on L2 acquisition of novel categories and work on the preceptual magnet effect, respectively). As a consequence, changes in the input pattern may be less likely to prompt change at the category label level within a generation than across generations. This line of reasoning supports a model in which usage-driven changes within categories set the stage for changes in the overall category system in acquisition, which then enables further usage-driven changes, and so on.
We present results from two sets of computer simulations of language change in which we explore the effects of language usage versus acquisition in an exemplar-based model. First, we present an exemplar model of morphological change in the lexicon based on the iterated learning paradigm of Kirby (2001). This type of model does not allow change in the number of morphological categories, but only in their contents. In this case, we show that expected frequency-based patterns of irregularity may arise either via iterated learning through transmission with no usage (Hare & Elman 1995, Kirby 2001) or via gradual, usage-based modifications within a single generation. Using this as an example, we make a case that first principles do not tell us whether intra-categorial changes of this sort require acquisition, usage or both, on analogy with the qualitative similarity of effects of bottlenecks versus drift in the domain of genetic drift (Suzuki et al. 1989).
In our second simulation, we investigate how category label change may influence the behavior of a model of vowel contrast maintenance. Here, we show that shifts in category contents through intra-generational usage set the stage for changes in the number of vowel categories, and that changes in the number of vowel categories in turn set the stage for further shifts in category contents through usage. In sum, we suggest that usage and acquisition make identifiably distinct contributions to change in different domains of language, and that each may influence the other in predictable ways. This model is consistent with suggestions that intergenerational acquisition reduces variation and accelerates changes that originated in usage (cf. Slobin 2004, Bybee to appear).