Researchers and developers of educational software have experimented with natural language processing (NLP) capabilities and related technologies since the 1960's. Automated essay scoring was perhaps the first application of this kind (Page 1966). Over a decade later, Writer's Workbench, a text-editing application, was developed as a tool for classroom teachers (MacDonald, Frase, Gingrich and Keenan 1982). Intelligent tutoring applications, though more in the spirit of artificial intelligence, were also being developed during this time (Carbonell 1970; Brown, Burton and Bell 1974; Stevens and Collins 1977; Burton and Brown 1982; Clancy 1987).