This paper studies the ‘formal quotation structure’ appearing in academic literature until the beginning to mid-20th century, and analyzes its syntactical structure to examine the grammaticalization process of the modern Korean auxiliary particle ‘-i-ran’. Major contents are summarized as follows. The specific subjects of this study are approximately 330 structures of the ‘objects of formal definition quotation’ extracted from academic literature from the 17th to 20th century. Among the 17th-century study subjects, 58% of the [1] type are in the form that involves heavy ellipsis such as ‘[A-i-ra]-n geos’, and only 42% of the [1] type rarely involve ellipsis, thus confirming that the form involving heavy ellipsis is slightly more frequent in occurrence. Among the 18th-century study subjects, only 34.6% did not involve ellipsis such as ‘[A-i-ra] h□-n□n geos’, from the [1] type, and 65.4% involve frequent ellipsis. Among the 19th-centurry study subjects, 72.7% of the subjects took the form involving frequent ellipsis, confirming the consistent rise in the occurrence of ‘objects of definition formal quotation’ with ellipsis from the 17th century. Among the early to mid-20th century study subjects, only one example of the format of the traditional ‘[A-i-ra]-ha-neun geos’, however, 45% of the [1] type involve the form that excludes the word that is being dressed by the adnominal clause(‘keos, mal’, etc) which was not frequently observed in the prior periods. 22% of the [1] type are the form ‘[A-i-ra]-neun geos’ that began to appear in the beginning of the 20th century, and the form ‘[A-i-ra]-n geos’ constitutes a significant 31% of the total [1] type. This indicates that the abbreviation of the ‘objects of definition formal quotation’ in the structure of ‘[A-i-ra]-ha-neun geos’ has become more common in use. Given the nature of the ‘object of definition formal quotation’, the structure of ‘[A-i-ra] h□-n□n geos’ and the auxiliary particle ‘-□n/-eun’ are used together and take the form similar to ‘[A-i-ra] h□-n□n geos□n’. The ellipsis structure is utilized actively from the 17th century, leading to the gradual use of the abbreviated form similar to ‘A-i-ran geos-eun’, which can be summarized as having been thus grammaticalized into the auxiliary particle ‘-i-ran’ in the modern grammar.