Syntactic Constructions and the Emergence of Event Types. A Computational Analysis of Verb Learning
The event type (or Aktionsart) expressed by a verb (state, activity, accomplish-ment or achievement, according to the classic Vendler’s classification) is a central com-ponent of its meaning. Psycholinguistic and linguistic data support each other in stress-ing the key role of event types for the representation of verbs in the mental lexicon. Moreover, event types crucially lie at the interface between lexicon and syntax.
Event-type categorization raises the issue of its cognitive status and origin, and is directly related to the problem of the interplay between lexical and grammar devel-opment. The purpose of this paper is to report on neural computational simulations sup-porting the claim that event types can be acquired by a general purpose learning model that extracts usage-based generalizations emerging from the distribution of verb tense-aspectual forms in specific syntactic constructions. The acquisition of event-type classes has been simulated with Self-Organizing Maps (SOMs) applied to linguistic input ex-tracted from the parental speech section of Italian CHILDES corpus. For these experi-ments, 30 Italian verbs have been selected according to their representativeness with re-spect to three major event types, i.e. state, activity and telic, the latter class encompass-ing both achievements and accomplishments. Event-type clusters have been boot-strapped by a SOM that exploits the verb distribution in morphological and syntactic constructions.
Computational simulations confirm the possibility to model event types as emergent categories deriving from the statistical distribution of linguistic data. Further-more, they may also shed new light in the way children actually exploit distributional information extracted from the linguistic input. In fact, a viable hypothesis is that event-type acquisition is the result of combining different clues coming from the verb morphological and syntactic constructions environment, showing a close interplay between lexical and syntactic development, consistently with the “lexical bootstrapping” hypothesis.