A study on measuring vocabulary knowledge and vocabulary size of Korean language learners.

Vocabulary research of Korean language learners has typically focused on selecting vocabulary items for educational vocabulary lists and searching for effective vocabulary instruction. However, measuring vocabulary has been discussed only in the sub-area of vocabulary test of TOPIK or as an instrument of test results of experimental studies, and not in measuring learners’ language ability. The instrument to measure vocabulary knowledge needs to develop to not only measure vocabulary size, but to also describe the characteristics of language learners' proficiency. This study conducted some pilot tests to measure vocabulary size and knowledge for advanced Korean learners and discussed some advantages and disadvantages of tests as an appropriate method of assessing vocabulary size knowledge. Measuring vocabulary size is limited by the selection of vocabulary items and the format of the test. The study used a random sample of 500 words from containing 50,000 words to estimate vocabulary size by a way of checking for whether the word was known or unknown. The result of this test was compared to the result of measuring vocabulary knowledge tests of academic words. In calculation of the correlation of these tests, an instrument to design for vocabulary measurement would be proposed.