한국어와 영어는 음소적 자소이고, 한자는 형태소적 자소이다. 그러나 한국어와 한자의 공통점은 별개의 자소로 기능을 하지 못하고, 자소들이 결합되어야 글자로서의 기능을 한다. 우리는 현재까지 한국어에서 이자소들의 결합을 ‘음절’로 인식하여 왔으나, 이글에서는 자소들의 결합을 ‘자절’로 보고자 한다. 훈민정음해례본에서는 ‘성음(成音)’과 ‘성자(成字)’를 구별하고 있다. ‘凡字必合而成音’의 구절에서 보듯 이초, 중, 종성이합해야음이된다고 했고, ‘初中終聲合而成字’처럼초, 중, 종성자를 합해야 글자를 이룰수있다고 했다. 지금까지 훈민정음제자원리에 대해서 《訓民正音》 해례의 ‘正音二十八字, 各象其形而制之’와 정인지 서문의 ‘象形而字倣古篆’에 대한 해석이 ‘육서(六書)’ 기원설과 관련지어 많은 연구가 이루어져 왔다. 이글에서는 자소 〈ㅇ〉의 자소적 기능을 기존의 ‘육서(六書)’와는 다른 한자자소론의 측면에서 한자와의 상호관련성을 살펴보았다. 한자의 자소는 크게 ‘구형소(構形素)’와 ‘기능소(機能素)’로 나뉜다. 구형소는 자형의 구조형태를 분석하고, 기능소는 평면적으로 자소가 담당하는 역할을 분석한다. 자소 〈ㅇ〉은 한자자소론과 관련하여 특별한 음의(音義) 없이 형체만 존재하면서, 특정한 자소와 결합했을 때만 일정한 의미를 갖는 구형소의 형체자소에 해당한다고 볼 수 있을 것이다.
Graphemics has attracted little attention as an object of main linguistic sphere. From linguistic development, the spoken language is prior to the written language. Hence, the written language has long been a replacement of spoken language and a secondary system of representation. Hence, the studies in the preceding have been very confused with transcription and writing system. Consequently, relatively little research has been carried out on graphemics, especially in Korean. Until now, there is, to my knowledge, no study on the graphemic correlation between the Korean Alphabet and Chinese character. The purpose of this study is to examine the graphemic correlation between two languages. Korean, together with English, is a representative of phonemic grapheme. However, the correspondence between grapheme and phoneme is ideally one-to-one, but we could seldom see the perfect one-to-one correspondence. This is caused by the systematic difference between grapheme and phoneme. In addition, Chinese character is a representative of logographic grapheme, which is to say, morphemic grapheme. Both languages have a common characteristic of making-up character. The main characteristic of the Korean writing system is that except for a few grammatical morphemes in archaic texts, no letter may stand alone to represent the elements of Korean language. Like the Chinese character, the Korean letters are combined into blocks. These blocks have been used a syllable as a meaning of character. But the syllable was not coincident with character. One of the structural differences is caused by the grapheme 〈ㅇ〉 in middle Korean. This study presents the graphemic function of 〈ㅇ〉 in middle Korean by comparing it with Chinese graphemics suggested by Park(2006). He classified the Chinese graphemes into constructional and functional grapheme. And then, he subdivided constructional graphemes into four; stroke, foundation, derivative and formal grapheme. In terms of Chinese graphemics, the grapheme <ㅇ> in middle Korean is included in formal grapheme. It does not solely function, but when it combines with specific grapheme, it becomes a meaningful unit. That is to say, although this grapheme does not function as a phonetic and semantic indicator, it is very essential to form a character.