A Compositional Semantics for Focusing Subjuncts

A Compositional Semantics for Focusing Subjuncts Daniel Lyons* MCC 3500 West Balcones Center Drive Austin, TX 78759, USA lyons~mcc.com Graeme Hirst Department of Computer Science University of Toronto Toronto, Canada MSS 1A4 gh~ai.toronto.edu Abstract A compositional semantics for focusing subjuncts-- words such as only, even, and also--is developed from Rooth's theory of association with focus. By adapting the theory so that it can be expressed in terms of a frame-based semantic formalism, a seman- tics that is more computationally practical is arrived at. This semantics captures pragmatic subtleties by incorporating a two-part representation, and recog- nizes the contribution of intonation to meaning. 1 Introduction Focusing subjuncts such as only, even, and also are a subclass of the sentence-element class of ad- verbials (Quirk et al., 1985). They draw attention to a part of a sentence the focus of the focusing subjunct--which often represents 'new' information. Focusing subjuncts are usually realized by adverbs, but occasionally by prepositional phrases. Focusing subjuncts emphasize, approximate, or restrict their foci. They modify the force or truth value of a sen- tence, especially with respect to its applicability to the focused item (Quirk et al., 1985, §8.116). 1.1 The problem with focusing subjuncts There are several reasons why developing any se- mantics for focusing subjuncts is a difficult task. First, focusing subjuncts are 'syntactically promiscuous'. They can adjoin to any maximal pro- jection. They can occur at almost any position in a sentence. Second, focusing subjuncts are also 'semantically promiscuous'. They may focus (draw attention to) almost any constituent. They can precede or fol- low the item that they focus, and need not be adja- cent to this item. The focus need only be contained somewhere within the syntactic sister of the focus- ing subjunct. Because of this behavior, it is difficult to determine the intended syntactic argument (ad- junct) and focus of a focusing subjunct. Sentences *The work described in this paper was done at the University of Toronto. such as those in (1) can be ambiguous, even when uttered aloud with intonational effects. 1 (1) 1. John could also (SEE) his wife from the doorway (as well as being able to talk to her). 2. John could also see (his WIFE) from the doorway (as well as her brother). 3. John could also see his wife (from the DOORway) (as well as from further inside the room). 4. John could also (see his wife from the DOORway) (as well as being able to do other things). Third, the location of intonational stress has an important effect on the meaning of a sentence con- taining a focusing subjunct. Sentences may be partly disambiguated by intonational stress: inter- pretations in which stress falls outside the intended focus of the focusing subjunct are impossible. For example, the sentence (2) *John could also see (his wife) from the DOORway. is impossible on the indicated reading, since stress on door cannot confer focus on his wife. On the other hand, stress does not help to disambiguate between readings such …

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