The purpose of this paper is to analyze the semantic structure of the three types of English articles—indefinite, definite, zero articles―with respect to the supposedly flexible boundaries of English nouns under the framework of Cognitive Grammar (Langacker 1987, 1991a, 1991b, 2000). To facilitate this, a new notion has been proposed: Boundedness Filter (BF), which is thought to play a decisive role in determining the activation or inactivation of noun boundaries in relation with the selection of corresponding articles. BF is supposed to operate in a variety of cognitive domains such as physical space for the indefinite article and psychological space for the definite article. This paper further claims that the count or mass-like property of a given noun is not fixed originally as prescribed in dictionaries or grammar books; rather, its boundary has a flexible feature depending upon the context in which it is used. This is why a common noun with its indefinite article as a boundary marker can sometimes be changed into a mass noun without any article. The BF and flexible characteristics of English noun boundaries can also be used to explain the reason that some apparently visible boundaries are not realized in physical space as indefinite articles.

1. Introduction
2. A Physical Boundary and the Indefinite Article
3. A Psychological Boundary and the Definite Article
4. BF and the Zero Article
5. Conclusion
References

• Kwanghee Lee(Hanyang University)