Disambiguating NN combinations with left/right stress

Disambiguating NN combinations with left/right stress James A. Hampton (hampton@city.ac.uk), Daniel Heussen (daniel@heussen.be), Zarah Argel (zarah_jayne@live.co.uk), Hasina Kanbi (hasina_k91@hotmail.com) Department of Psychology, City University London, Northampton Square, London EC1V OHB, UK Abstract An interesting subclass of Noun-noun combinations in English can take two meanings depending on whether the first or second word is stressed in speech. A BRICK factory is one that makes bricks, whereas a brick FACTORY is one made of brick. An explanation is offered in terms of a bias for nouns from particular ontological categories to trigger particular semantic interpretations for a combination, together with the proposal that the unstressed noun provides the relation to be used. The explanation is tested in three empirical studies. Keywords: NN combination, concepts, compounds, meaning, ambiguity, stress Introduction Noun-noun compounds are found in many languages. They are the result of placing two nouns together in order to create a compound noun phrase with a new meaning (Gleitman & Gleitman, 1970; Levi, 1978). The first noun— the modifier—serves to specialise the meaning of the second noun—the head. To take the example of cheese knife, the head noun knife determines the kind of thing involved—a cheese knife is a knife—while the modifier cheese specifies that it is designed for use with cheese. 1 Looking at noun-noun compounds in English it is possible to differentiate those that are constructed on the fly to meet the communicative needs of a given moment from those that long ago entered the lexicon. A good example of the former is Downing’s (1977) famous apple-juice seat to indicate the seat at a table at which the person drinking apple-juice should sit, whereas examples of the latter are toothpaste or lunch box. As they enter the lexicon, compounds in English may be lexicalized as single orthographic words (e.g., snowman), or optionally hyphenated (e.g., pigeon-hole), while others have two-word spellings (e.g., taxi driver). Lexicalization involves a number of changes in the status of a phrase. In particular, lexicalized compounds are also more likely to lack semantic transparency, and hence to appear in dictionaries. The meaning of such non-transparent phrases must be acquired through hearing them in context, rather While familiar compounds like cheese knife have a conventional meaning, given a sufficiently rich context, they can take on an indefinite number of alternative meanings—such as a knife made of cheese, or the knife given as a trophy to the prize winning cheese maker. We are concerned here with the default meaning that first comes to mind in the absence of such a context. than being computable from the individual meanings alone. Examples like beer garden, water glass, or wine lake cannot be easily understood without appeal to knowledge external to the meaning of the two individual words. In addition to the many lexicalized compounds in English, it is also possible to create new forms which can be readily understood. People have little trouble understanding new expressions like camel field, or student gardener, even though they may not have come across these combinations before. An explanation for this productivity was suggested by Gagne and Shoben (1997) in their CARIN model of Noun-Noun (NN) combinations. Earlier, Levi (1978) had proposed that the majority of compounds employ one of about 12 semantic relations, such as USE, LOCATION, MATERIAL COMPOSITION or CAUSE. Gagne and Shoben suggested that each noun in a person’s vocabulary may be associated in memory with the relations that it most commonly enters into, as either a modifier or a head. Thus for example mountain as a modifier would normally indicate a location as in mountain goat, or mountain village. On the other hand magazine as a head would normally use an informational “about” relation as in train magazine or psychology magazine. When the two are put together to form mountain magazine, a search is instigated to find a plausible meaning. Since a magazine about mountains strikes most people as more plausible than a magazine in the mountains, in this case the head noun ends up dictating the preferred meaning of the phrase. In the search for a plausible meaning, two equally plausible meanings can sometimes arise, each based on one of the two nouns and their preferred semantic relations, so that the compound is ambiguous. Kamp and Partee (1995) cite the example of a brick factory, which can either mean a factory that makes bricks or a factory that is made of brick. They also point out that the stress pattern employed when speaking the phrase can disambiguate its meaning. Thus one can compare (1) and (2): (1) a BRICK factory = a factory that makes bricks (2) a brick FACTORY = a factory made of brick. The account offered by Kamp and Partee is that the ambiguity relates to the use of two distinct syntactic forms. They suggest, following Bloomfield, (1933: 228) and Chomsky and Halle’s (1968: 15-18) Compound Rule, that left stress is a general signal in English that the phrase is a compound, meaning that its semantics will depend on local