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One of the defining properties of human language is the abundance of potentially unbounded dependencies between elements in a sentence. And yet, how speakers formulate dependencies in sentence production is still poorly understood. Here we examine the timing of verb planning in sentences involving across-the-board and parasitic gap constructions. Using a new task we call the Sentence-Word Interference task, we show that speakers plan the verb of a secondary clause before sentence onset, but selectively when producing across-the-board sentences and not when producing parasitic gap sentences. Based on this timing contrast, we argue that speakers plan verbs predominantly before the production of their dependents, but only when verbs and their dependents engage in both conceptual and direct syntactic relationships. More broadly, the current study suggests that sentence planning is constrained by syntactic relationships that are not reducible to conceptual relationships or to surface word order.

This study examines how speakers produce sentences containing tough construction ('tough' sentences), like the following: The dog is tough to please. We will examine when speakers plan the embedded verb ("please" in the example above) when producing tough sentences. In our past studies, we found that speakers plan the lemma representation of verb roots before starting to speak their underlying object arguments, but not before their underlying subject arguments. The current study test whether speakers plan the verb lemma before the articulation of the matrix subject, which under some but not other theories is an underlying object of the embedded verb.

Data and analysis scripts for "Syntactic category constrains lexical competition in speaking."

This experiment investigates the production of the sentences involving “raising to object” and “object control” sentences. For example: (1) The boy believed the dog to like the cat. (2) The boy taught the dog to like the cat. This experiment investigates the production of sentences involving “raising to object” and “object control” sentences. For example: The boy believed the dog to like the cat. The boy taught the dog to like the cat. In both sentences, “the dog” is the subject of the embedded verb “like” semantically. Also, in both cases, “the dog” is the syntactic object of the matrix verb “believed/taught,” as indicated by the fact that a pronoun would receive an accusative case. However, only in (2), “the dog” is the semantic object of the matrix verb “taught.” For this reason, those two constructions, despite surface similarity, are hypothesized to involve two different underlying structures. This experiment examines how speakers plan those sentences, and in particular, we hypothesize, according to some theories of syntax, there is a clausal boundary between “believed” and “the dog” but not between “taught” and “the dog.” Based on the an independent psycholinguistic hypothesis that two words interference more within the same clause, we predict that “the dog” and “the cat”, two words with similar meanings, interfere more in the raising to object sentences like (1) than in the object control sentences like (2).

Humans use their grammatical knowledge in more than one way. On one hand, they use it to understand what others say. On the other hand, they use it to say what they want to convey to others (or to themselves). In either case, they need to assemble the structure of sentences in a systematic fashion, in accordance with the grammar of their language. Despite the fact that the structures that comprehenders and speakers assemble are systematic in an identical fashion (i.e., obey the same grammatical constraints), the two ‘modes’ of assembling sentence structures might or might not be performed by the same cognitive mechanisms. Currently, the field of psycholinguistics implicitly adopts the position that they are supported by different cognitive mechanisms, as evident from the fact that most psycholinguistic models seek to explain either comprehension or production phenomena. The potential existence of two independent cognitive systems underlying linguistic performance doubles the problem of linking the theory of linguistic knowledge and the theory of linguistic performance, making the integration of linguistics and psycholinguistic harder. This thesis thus aims to unify the structure building system in comprehension, i.e., parser, and the structure building system in production, i.e., generator, into one, so that the linking theory between knowledge and performance can also be unified into one. I will discuss and unify both existing and new data pertaining to how structures are assembled in understanding and speaking, and attempt to show that the unification between parsing and generation is at least a plausible research enterprise. In Chapter 1, I will discuss the previous and current views on how parsing and generation are related to each other. I will outline the challenges for the current view that the parser and the generator are the same cognitive mechanism. This single system view is discussed and evaluated in the rest of the chapters. In Chapter 2, I will present new experimental evidence suggesting that the grain size of the pre-compiled structural units (henceforth simply structural units) is rather small, contrary to some models of sentence production. In particular, I will show that the internal structure of the verb phrase in a ditransitive sentence (e.g., The chef is donating the book to the monk) is not specified at the onset of speech, but is specified before the first internal argument (the book) needs to be uttered. I will also show that this timing of structural processes with respect to the verb phrase structure is earlier than the lexical processes of verb internal arguments. These two results in concert show that the size of structure building units in sentence production is rather small, contrary to some models of sentence production, yet structural processes still precede lexical processes. I argue that this view of generation resembles the widely accepted model of parsing that utilizes both top-down and bottom-up structure building procedures. In Chapter 3, I will present new experimental evidence suggesting that the structural representation strongly constrains the subsequent lexical processes. In particular, I will show that conceptually similar lexical items interfere with each other only when they share the same syntactic category in sentence production. The mechanism that I call syntactic gating, will be proposed, and this mechanism characterizes how the structural and lexical processes interact in generation. I will present two Event Related Potential (ERP) experiments that show that the lexical retrieval in (predictive) comprehension is also constrained by syntactic categories. I will argue that the syntactic gating mechanism is operative both in parsing and generation, and that the interaction between structural and lexical processes in both parsing and generation can be characterized in the same fashion. In Chapter 4, I will present a series of experiments examining the timing at which verbs’ lexical representations are planned in sentence production. It will be shown that verbs are planned before the articulation of their internal arguments, regardless of the target language (Japanese or English) and regardless of the sentence type (active object-initial sentence in Japanese, passive sentences in English, and unaccusative sentences in English). I will discuss how this result sheds light on the notion of incrementality in generation. In Chapter 5, I will synthesize the experimental findings presented in this thesis and in previous research to address the challenges to the single system view I outlined in Chapter 1. I will then conclude by presenting a preliminary single system model that can potentially capture both the key sentence comprehension and sentence production data without assuming distinct mechanisms for each.