Introduction to the special issue: parsimony and redundancy in models of language

Multiword units lead to errors of commission in children's spontaneous production: "What corpus data can tell us?*"

Psycholinguistic research over the past decade has suggested that children's linguistic knowledge includes dedicated representations for frequently‐encountered multiword sequences. Important evidence for this comes from studies of children's production: it has been repeatedly demonstrated that children's rate of speech errors is greater for word sequences that are infrequent and thus unfamiliar to them than for those that are frequent. In this study, we investigate whether children's knowledge of multiword sequences can explain a phenomenon that has long represented a key theoretical fault line in the study of language development: errors of subject‐auxiliary non‐inversion in question production (e.g., “why we can't go outside?*”). In doing so we consider a type of error that has been ignored in discussion of multiword sequences to date. Previous work has focused on errors of omission – an absence of accurate productions for infrequent phrases. However, if children make use of dedicated representations for frequent sequences of words in their productions, we might also expect to see errors of commission – the appearance of frequent phrases in children's speech even when such phrases are not appropriate. Through a series of corpus analyses, we provide the first evidence that the global input frequency of multiword sequences (e.g., “she is going” as it appears in declarative utterances) is a valuable predictor of their errorful appearance (e.g., the uninverted question “what she is going to do?*”) in naturalistic speech. This finding, we argue, constitutes powerful evidence that multiword sequences can be represented as linguistic units in their own right.

Abstract knowledge versus direct experience in processing of binomial expressions

We ask whether word order preferences for binomial expressions of the form A and B (e.g. bread and butter) are driven by abstract linguistic knowledge of ordering constraints referencing the semantic, phonological, and lexical properties of the constituent words, or by prior direct experience with the specific items in questions. Using forced-choice and self-paced reading tasks, we demonstrate that online processing of never-before-seen binomials is influenced by abstract knowledge of ordering constraints, which we estimate with a probabilistic model. In contrast, online processing of highly frequent binomials is primarily driven by direct experience, which we estimate from corpus frequency counts. We propose a trade-off wherein processing of novel expressions relies upon abstract knowledge, while reliance upon direct experience increases with increased exposure to an expression. Our findings support theories of language processing in which both compositional generation and direct, holistic reuse of multi-word expressions play crucial roles.