On productivity

Language learning is a remarkably robust process. The child is incredibly good at recognizing systematic regularities even when faced with lexically and contextually restricted exceptions This paper sketches out a preliminary model that recognizes productive processes and exceptions as such; accordingly, the learner can proceed to internalize each as different kinds of linguistic knowledge. We argue that if a linguistic process is conjectured to be productive, then having exceptions to it can add (surprisingly) significant cost to its online processing. Empirically, we explore these issues in the domain of morphology, which leads to finer-grained analyses of a number of well-known morphological problems. We also briefly discuss how the methodology and results of this work may generalize to syntactic learning.