tailieunhanh - Báo cáo khoa học: "CORRECTING ILLEGAL NP OMISSIONS USING LOCAL FOCUS"

Linda Z. Suri 1 Department of Computer and Information Sciences University of Delaware Newark DE 19716 Internet: suri@ INTRODUCTION The work described here is in the context of developing a system that will correct the written EnliSh of native users of American Sign Language SL) who are learning English as a second language. In this paper we focus on one error class that we have found to be particularly prevalent: the illegal omission of NP's. Our previous analysis of the written English of ASL natives has led us to conclude that language transfer (LT) can explain many errors, and should. | CORRECTING ILLEGAL NP OMISSIONS USING LOCAL FOCUS Linda z. Suri1 Department of Computer and Information Sciences University of Delaware Newark DE 19716 Internet suri@ 1 INTRODUCTION The work described here is in the context of developing a system that will correct the written English of native users of American Sign Language ASL who are learning English as a second language. In this paper we focus on one error class that we have found to be particularly prevalent the illegal omission of NP s. Our previous analysis of the written English of ASL natives has led us to conclude that language transfer LT can explain many errors and should thus be taken advantage of by ăn instructional system Suri 1991 Suri and McCoy 1991 . We believe that many of the omission errors we have found are among the errors explainable by LT. Lillo-Martin 1991 investigates null argument structures in ASL. She identifies two classes of ASL verbs that allow different types of null argument structures. Plain verbs do not carry morphological markings for subject or object agreement and yet allow null argument structures in some contexts. These structures she claims are analogous to the null argument structures found in languages like Chinese that allow a null argument if the argument co-specifies the topic of a previous sentence Huang 1984 . Such languages are said to be discourse-oriented languages. As it turns out our writing samples collected from deaf writers contain many instances of omitted NP s where those NP s are the topic of a previous sentence and where the verb involved would be a plain verb in ASL. We believe these errors can be explained as a result of the ASL native carrying over conventions of discourse-oriented ASL to sentence-oriented English. If this is the case then these omissions can be corrected if we track the topic or in computational linguistics terms the local focus and the actor We propose to do this by developing a modified version of Sidner s focus .