Multiple nominative construction in Korean and its second language acquisition by adult English speakers

The thesis deals with the problem of ultimate attainment in second language acquisition research. In other words, it is about whether second language learners can achieve native-like linguistic competence of their target language. Particularly, it investigates to what extent second language learners reach a steady state in their acquisition, and whether the steady state of native speakers qualitatively differs. The research presented in the thesis supports the idea that the ultimate attainment of a second language is partially achievable, which has been dubbed as 'Interface Hypothesis.' The hypothesis insists that interfaces between linguistic modules, such as syntax-morphology interface and syntax-pragmatics interface, present difficulty in second language acquisition up to and including ultimate attainment, while pure syntax can be acquired successfully according to the increased general proficiency of adult second language speakers.;For this purpose, the multiple nominative construction in Korean was taken as a testing ground in the thesis. The construction refers to the situation where, unlike English, more than one nominative phrase is permitted in a single clause. This construction is ideal to test if ultimate attainment is partially attainable and what area is vulnerable, since the two different types of construction, Nominative Object Construction (NOC) and Multiple Subject Construction (MSC), manifest different grammatical modules they implicate. NOC is not related to any interface and is simply licensed by a pure syntactic operation. On the other hand, MSC requires correct functioning of the syntax-pragmatics interface. Because of this difference in grammatical modules required, it is predicted that the acquisition of the latter (MSC) is more constrained than the former (NOC). The results of the experiments conducted in the thesis confirm this prediction. For NOC, beginning and intermediate learners evidence their incompleteness in its acquisition. However, once complete restructuring of interlanguage grammars is achieved with respect to proper Korean syntactic case mechanisms, the results of the experiments show that these errors are overcome. In contrast, such improvement is not evident with respect to MSC, which requires syntax-pragmatic licensing, indicating greater difficulty with acquisition of the syntax-pragmatics interface. The research in the thesis concomitantly provides quantitative L2 acquisition data for the still-controversial issue concerning the distinction between NOCs and MSCs in Korean.