The purpose of this study is to show that the primary function of the construction of bound noun is to express the modality. In this paper we suggest the reasons why the construction of bound noun refers to the modality such as followings : (1) the examination of the semantic function on the construction of bound noun in itself, (2) Korean is the speaker-hearer oriented language, (3) the various marking of modality in the viewpoint of the typology(language universals) (4) the extension of modality in English.
In these constructions of bound noun, the core element which refers to the modality is the bound noun. The preceding element of the bound noun is to connect the proposition with the bound noun and the following one of the bound noun is a kind of support verb which makes the bound noun+proposition as predicates. Therefore the bound noun is called as lexical modal and the modals are summarized such as: (1) lexical modals (bound noun, auxiliary verb) (2) grammatical modals (ending, particle).