| To understand how humans comprehend even a simple sentence, one needs to investigate how various types of linguistic information are processed and how they interact with each other during comprehension. The primary goals of this dissertation research were to investigate the following issues using an event-related brain potential (ERP) technique: (1) the timecourse of interaction between syntactic and semantic information during sentence comprehension, (2) the nature of the earlier and later phases of syntactic processing, and (3) the neural substrates of language processing associated with individuals with different linguistic profiles.; The first study examined the interaction between syntax and semantics during online sentence comprehension in monolingual native English speakers. The results suggested that semantic and syntactic information interact during not only the later phase but also the earlier phase of syntactic processing. The second study investigated whether syntactic and semantic information interact with each other in a similar manner in three groups of individuals that differed in linguistic profiles. The comparison of two native English-speaker groups differing in grammatical proficiency suggested that those with above-average proficiency are more efficient in syntactic processing than those with average proficiency. The results from a third group of non-native English speakers exposed to English after puberty suggested that they rely on semantic information during syntactic processing when semantic information is available. However, when semantic information is unavailable, they process syntactic information in a more native-like manner. The third study addressed a methodological issue that arose in the first two studies. The fourth study investigated the nature of the earlier and later phases of syntactic processes. The results suggested that the earlier phase of syntactic processing, which in late learners was modulated by the presence or absence of semantic information, is not entirely independent of the availability of cognitive resources, and that the later phase involves processes associated with the evaluation of syntactic well-formedness.; Together these findings revealed the neural substrates of syntactic processing associated with differences in linguistic profiles and suggested that the availability and allocation of cognitive resources is an important factor in characterizing differences in syntactic processing among individuals with different linguistic profiles. |
