If the purpose of an assessment is diagnosing examinees’ knowledge states to improve their learning, more fine-grained information than the overall level of their ability is necessary. Recent advances in diagnostic assessment triggered the development of cognitive diagnosis models (CDMs), such as the deterministic inputs, noisy “And” gate (DINA) model. Although CDMs for language assessments have been applied to reading or listening test data, a CDM may produce more practical results if the construct to measure has specific and well-defined skill attributes as in a grammar assessment. For this study, a grammar test consisting of 40 multiple-choice items was administered to 3,000 Korean learners of English as a foreign language. From the test items, a Q-matrix, which is an essential tool for CDMs, was constructed based on six grammar skills. As a result, skill profiles were obtained for all examinees. This diagnostic information can be used for tailored instruction. Issues with regard to applications of CDMs to language assessments are also discussed.

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.