crocker@TIS-W.ARPA (Stephen D. Crocker) (08/26/88)
Date: Sun, 14 Aug 88 01:34 EDT From: Stephen D. Crocker <crocker@tis-w.arpa> To: AIList-REQUEST@AI.AI.MIT.EDU Subject: open versus closed classes of words in English grammar McGuire replied to Nagle's query about open versus closed classes of words in English grammar, viz nouns, verbs, adjectives and adverbs are open and conjunctions, articles, prepositions, etc. are closed. He then comments: > While I'm familiar with this distinction, and think that it may have > been around in linguistics for quite some while (Bernard Bloch maybe?), > I don't remember it being used much. The only references that spring to > mind are some studies in speech production and slips of the tongue done > in the 70s by Anne Cunningham (she's a Brit though I'm not sure of her > last name) and maybe Victoria Fromkin claiming that less errors are > associated with closed class words and that they play some privileged role > in speech_production/syntax/lexical_access/the_archetecture_of_the_mind. I recall in the mid or late 60's reading about a parser built in the UK that relied heavily on the closed classes -- I think the term was "functions words". I believe the parser determined which class the other words were in, noun, verb, etc., solely by the slots created from the function words. To that parser, McGuire's four example sentences would be equivalent to "Foo frobbed fie" "Foo has frobbed fie" "Foo might frob fie" "Foo fums to frob fie" The parser was exceedingly fast, but I don't remember any follow up from this work. If pressed, I can probably find a reference, but I suspect many readers of this digest are more familiar with the work than I. In the speech understanding work of the early 70's, I found it interesting that the functions words played a lesser role than might have been expected because they tended to be unstressed when spoken and hence reduced in duration and clarity. I don't recall whether they played a major role in any of the later systems. It's evident that humans depend on these words and learn new open class words from context created by a combination of the closed class words and known meanings for the open class words elsewhere in the sentence. This suggests that one attribute to look for in truly mature speech understanding systems is reliable "hearing" of function words. I'd be interested if anyone knows the current status of speech understanding in this area. Along somewhat separate lines, Balzer at ISI built a rudimentary parser for English in the early 70's. It was aimed at extracting formal program specs from an English specification. His key example was based heavily on interpeting the closed classes and treating the open classes as variables.