The present experimental study explores developmental characteristics of Korean EFL learners’ English negatives and yes-no interrogatives. Adopting the functional category acquisition framework within the UG theory, this study investigated 12 elementary and secondary school students’ interlanguage grammar by elicited production. The results showed that the learners’ interlanguage grammar developed gradually from VP to IP and CP structures in English negatives. However, their interlanguage grammar did not show gradual developmental tendency in yes-no interrogatives. The acquisition rate of negatives generally increased with the learners’ level whereas there existed individual variation in the acquisition rate and developmental aspect of yes-no interrogatives. This result suggests that CP structures instantiated by yes-no interrogatives seem to be acquired from the initial stage by some learners.

Universal grammar has exerted meaningful influence on the development of second language acquisition theories. SLA researchers working within UG have addressed the question whether second language developments are constrained by universal language principles. This paper reviews current developments in UG-based SLA research with a view to providing a better understanding of the role of UG principles in foreign language sentence structure development.