Linguists debate the nature of grammatical knowledge. Many argue it is innate knowledge of syntactic structure that we use when generating utterances; others argue it emerges from linguistic experience, and forms exemplars for modeling novel utterances. Yet, still others argue that grammatical forms are processed in parallel by both types of knowledge (innate or otherwise), and crucially, that these two processing routes compete with each other.
Our objective is to support the dual route argument with a corpus study illustrating the interaction of these two types of knowledge. We interpret two proxies as indicators of these two types of knowledge: syntactic complexity for generative knowledge and dispersion for emergent knowledge. Previous psycholinguistic work has shown that increased syntactic complexity correlates with increased judgment reaction times. Conversely, increased dispersion correlates with decreased judgment reaction times. If these two processing mechanisms compete, then we predict an interaction: specifically, we hypothesize that the more dispersed a linguistic form is, the less influence syntactic complexity has.
We conducted a mixed-effects logistic regression analysis on case marker omissions in Japanese. Our results show that a casual speech style, a dispersed object–verb pair, and a syntactically simple noun phrase for the object correlate with increased case marker omission. More importantly, syntactic complexity and dispersion interact: as dispersion decreases, the estimated coefficient for syntactic complexity increases. These results support the claim that generative knowledge and emergent knowledge compete during language processing.