The purpose of this study is to examine the characteristics of the "gulda" phrase and reveal that "gulda" is an auxiliary predicate. The study divided "gulda" phrases into three categories: "-ge gulda", "-i/he gulda" and other "gulda" phrases, and analyzed what semantic features each phrase has and what function the preceding element performs. The result is that "gulda" is a predicate that cannot be used alone and must have a preceding element. Previous studies often saw preceding elements used together with "gulda" as essential adverbs, and treated their mediums "-ge" and "-i/he" as adverbial endings. However, through various examples, this study demonstrated that it is reasonable to regard '-ge' or '-i/he' as an auxiliary linking ending rather than an adverbial ending. In other phrases, 'gulda' was found to be used mainly in conjunction with descriptive adverbs or postpositions such as “cheorum, gatchi", which means that 'gulda' was not yet fully grammaticalized, so it also has the characteristics of a primary predicate. It was also found that 'gulda' as an auxiliary predicate functions as 'emphasis' or 'profanity'.
Furthermore, an examination of the grammaticalization of "gulda" found that the most typical form of "gulda" in the middle and modern period of Korean language was "-i/he gulda" phrase, and that "-ge gulda" phrase appeared after the 18th century. During the middle and modern period of Korean language, "gulda" served as an independent predicate in the sentence, and there were no clear restrictions on the preceding words. In front of "gulda," the form of "noun+postposition" such as subject and adverbial words was freely used, and linking endings such as "-i/he, -ge, -dorok, -ya" were combined with "gulda" without specific restrictions. In addition, unlike contemporary Korean language, adverbs that came before "gulda" could come in various forms such as "grung, gru, iru, gyeoh, and mopsi." Given these characteristics, "gulda" is a predicate in the 1st stage of grammaticalization, and it can be said that it is undergoing a change from a primary predicate to an auxiliary predicate. Therefore, it is possible to identify "gulda" with the characteristics of a primary predicate in contemporary Korean language, and "gulda" which has the characteristics of an auxiliary predicate also coexists.
The purpose of this study is to reveal that "gulda" is an auxiliary predicate, and it examined "gulda" phrases of the middle and modern period of Korean language from historical materials and "gulda" phrases of contemporary Korean language in various corpus materials. As a result, it was found that 'gulda' is a predicate in the grammaticalization phase from a primary predicate to an auxiliary predicate.