A Note on Syntactic Licensing of Null Subjects as a Parametric Variation Among Languages Sunja Lee* & Munhong Choe** Abstract: One of the fundamental assumptions in formal linguistics is that a noun phrase in a clause is licensed only when its reference is identified and it is case-marked for thematic role assignment. However, languages differ in respect of whether a sentence requires an explicit, as opposed to implicit or understood, subject. In the literature, two methods of licensing such null subjects have been discussed; they tend to occur in languages with rich subject-verb agreement morphology like Italian and in so-called topic-prominent languages like Korean. The purpose of this study is to critically review some of the influential accounts of this peculiar variation among languages and provides a synthetic conclusion such that licensing null subjects is an arbitrary property to a large extent. There is no systematic way to predict whether or not a particular language permits null subjects on the mere basis of the morphosyntactic characteristics of the language. Key Words: Licensing Null Subjects, Subject-verb Agreement, Topic-prominent Languages, Peculiar Variation, Arbitrary Property