The objective of this study is to review, and categorize the constructed responses about the phoneme concepts in the 2015 NAEA (National Assessment of Educational Achievement) in the Middle School level Korean Language, the result of which will be used to understand the trends in the grammar misconceptions. The incorrect responses to questions asking about the basic concept of phoneme had been categorized into the following: Misconceptions of concept dimensions, misconception of phoneme system, and the misconception of important role the phoneme plays in the grammar system. Therefore the report suggests that when teaching basic phoneme, the education should be reconstructed so that it focuses less on learning new concepts but rather on the grammar.