This study conducted an investigation on the children of age from 24 months to 6 years to explore the development aspect of nominalizer ‘-gi’ appearing in spoken language. Children’s use of nominalizer ‘-gi’ began to be developed around 30 months old and it was used more frequently than noun-derived suffix. The aspect of syntactical development for nominalizer ‘-gi’ was analyzed focusing on the characteristics appearing according to each location of noun combined with ‘-gi’ in a sentence. First, at the locations of subjects, the predicates expressing emotion assessment and the predicates expressing probability were found to be co-described with nominalizer ‘-gi’, and at the locations of objects, ‘-hada’ appeared with very high frequency as a superior predicate of nominalizer ‘-gi’. Even at the locations of both subjects and objects, postpositional particles were omitted very frequently. At the locations of predicates, there appeared various forms such as ‘-gi-ida’ form, ‘-gi’ terminating form and auxiliary predicate form composition. At the locations of adnominal phrase, nominalizing ending ‘-gi’ that performs a function to modify the nouns ‘ddaemun, jeon’ was found. At the locations of adverbial phrase, there appeared a form combined with adverbial postposition. The appearing locations in a sentence showed a specific developmental order. In the vertical data, the first appearance was at the locations of objects and predicates with very high frequency. It was followed by the locations of subjects, lastly by the locations of adnominal phrase and adverbial phrase with not much frequency. In the horizontal data, it showed the most frequency at the locations of predicates and followed by subject, object, adverbial phrase and adnominal phrase. Particularly, the appearance of nominalizer ‘-gi’ at the location of predicate also showed a characteristic that the number of speakers who used this nominalizer increased as their age increased.