A Longitudinal Study on Lexical Use Aspects of Korean Learners

The purpose of this study is conducting longitudinal examination on lexical use development aspects of Korean learner. Written texts ranging from level 1 to level 4 were collected by targeting one learner of Korean regular course affiliated with university. In order to observe lexical use aspects, lexical diversity, lexical density, and lexical sophistication corresponding to components of lexical abundance were estimated. As a result, it has been found that lexical abundance of achievement assessment written text was lower than written texts from classes. Lexical diversity was estimated by using D value. D value increased as Korean learning period and Korean proficiency increased. Likewise with D value, lexical sophistication also increased as Korean language learning period and proficiency increased. This proves that proficiency influences lexical diversity and quality. Lexical density value did not differ greatly from lexical diversity and lexical sophistication. However, in the intermediate course, the amount of content words corresponding to lexical density estimating categories increased sharply. This result shows that texts created by learner have vast information according to proficiency. This study is meaningful as the basic material of lexical ability estimation even though it is a mere longitudinal study which targeted one person(Chung-Ang University).