Semantic interpretation against ambiguity

We describe a new approach to semantic interpretation in natural language understanding, and mechanisms for both lexical and structural disambiguation that work in concert with the semantic interpreter. Traditionally, translation from the parse tree of a sentence to a semantic representation (such as frames or procedural semantics) has always been the most ad hoc part of natural language understanding systems. However, recent advances in linguistics, most notably the system of formal semantics known as Montague semantics, suggest ways of putting semantic interpretation onto a cleaner and firmer foundation. Absity, the system we describe, is a Montague-inspired semantic interpreter. Like Montague formalisms, our semantics is compositional by design and is strongly typed, with semantic rules in one-to-one correspondence with the meaning-affecting rules of a Marcus parser. We have replaced the Montague semantic objects--functors and truth conditions--with elements of the frame language Frail. Absity's partial results are always well-formed Frail objects. A semantic interpreter must be able to provide feedback to the parser to help it handle structural ambiguities. In Absity, this is done by the "Semantic Enquiry Desk", a process that answers the parser's questions on semantic preferences. Disambiguation of word senses and of case slots is done by a set of procedures, one per word or slot, each of which determines its correct sense in cooperation with the others. A partially disambiguated procedure's remaining possibilities are well-formed Frail objects that can be seen and used by other processes, including the Semantic Enquiry Desk, just as a person can see many of the details of a partly developed "instant" photograph. It is from the fact that partial results are always well-formed semantic objects that the system gains much of its power. This, in turn, comes from the strict correspondence between syntax and semantics in Absity. The result is a foundation for semantic interpretation that we believe to be superior to previous approaches.