Toward a lexicalized grammar for interlinguas

In this paper we present one aspect of our research on machine translation (MT): capturing the grammatical and computational relation between (i) the interlingua (IL) as defined declaratively in the lexicon and (ii) the IL as defined procedurally by way of algorithms that compose and decompose pivot IL forms. We begin by examining the interlinguas in the lexicons of a variety of current IL-based approaches to MT. This brief survey makes it clear that no consensus exists among MT researchers on the level of representation for defining the IL. In the section that follows, we explore the consequences of this missing formal framework for MT system builders who develop their own lexical-IL entries. The lack of software tools to support rapid IL respecification and testing greatly hampers their ability to modify representations to handle new data and new domains. Our view is that IL-based MT research needs both (a) the formal framework to specify possible IL grammars and (b) the software support tools to implement and test these grammars. With respect to (a), we propose adopting a lexicalized grammar approach, tapping research results from the study of tree grammars for natural language syntax. With respect to (b), we sketch the design and functional specifications for parts of ILustrate, the set of software tools that we need to implement and test the various IL formalisms that meet the requirements of a lexicalized grammar. In this way, we begin to address a basic issue in MT research, how to define and test an interlingua as a computational language — without building a full MT system for each possible IL formalism that might be proposed.