Bilingual Hebrew-English Generation of Possessives and Partitives: Raising the Input Abstraction Level

Bilingual Hebrew-English Generation of Possessives and Partitives: Raising the Input Abstraction Level Yael Dahan Netzer and Michael Elhadad Ben Gurion University Department of Mathematics and Computer Science, Beer Sheva, 84105, Israel (yaeln I elhadad) @cs. bgu. ac. il Abstract Syntactic realization grammars have tradi- tionally attempted to accept inputs with the highest possible level of abstraction, in or- der to facilitate the work of the compo- nents (sentence planner) preparing the in- put. Recently, the search for higher ab- straction has been, however, challenged (E1- hadad and Robin, 1996)(Lavoie and Ram- bow, 1997)(Busemann and Horacek, 1998). In this paper, we contribute to the issue of selecting the "ideal" abstraction level in the input to syntactic realization grammar by considering the case of partitives and pos- sessives in a bilingual Hebrew-English gen- eration grammar. In the case of bilingual generation, the ultimate goal is to provide a single input structure, where only the open- class lexical entries are specific to the lan- guage. In that case, the minimal abstraction required must cover the different syntactic constraints of the two languages. We present a contrastive analysis of the syntactic realizations of possessives and par- titives in Hebrew and English and conclude by presenting an input specification for com- plex NPs which is slightly more abstract than the one used in SURGE. We define two main features -possessor and rejLset, and • discuss how the grammar handles complex syntactic co-occurrence phenomena based on this input. We conclude by evaluating how the resulting input specification language is appropriate for both languages. 1 Introduction One of the first issues to address when se- lecting a syntactic realization component is whether its input specification language fits the desired application. Traditionally, syntactic realization components have at- tempted to raise the abstraction level of in- put specifications for two reasons: (1) to pre- serve the possibility of paraphrasing and (2) to make it easy for the sentence planner to map from semantic data to syntactic input As new applications appear, that can- not start generation from a semantic in- put because such an input is not available (for example re-generation of sentences from syntactic fragments to produce summaries (Barzilay et al., 1999) or generation of com- plex NPs in a hybrid template system for business letters (Gedalia, 1996)), this moti- vation has lost some of its strength. Con- sequently, "shallow surface generators" have recently appeared (Lavoie and Rambow, 1997) (Busemann and Horacek, 1998) that require an input considerably less abstract than those required by more traditional re- alization components such as SURGE (E1- hadad and Robin, 1996) or KPML (Bate- man, 1997). In this paper, we contribute to the de- bate on selecting an appropriate level of ab- straction by considering the case of bilin- gual generation. We present results ob- tained while developing the HUGG syntactic realization component for Hebrew (Dahan- Netzer, 1997). One of the goals of this sys- tem is to design a generator with an input specification language as similar as possible to that …

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