An empirical analysis of constructing non-restrictive NP modifiers to express semantic relations

Abstract

It is not a rare phenomenon for human written text to use non-restrictive NP modifiers to express essential pieces of information or support the situation presented in the main proposition containing the NP, for example, "Private Eye, which couldn't afford the libel payment, had been threatened with closure." (from Wall Street Journal) Yet no previous research in NLG investigates this in detail. This paper describes corpus analysis and a psycholinguis-tic experiment regarding the acceptability of using non-restrictive NP modifiers to express semantic relations that might normally be signalled by 'because' and 'then'. The experiment tests several relevant factors and enables us to accept or reject a number of hypotheses. The results are incorporated into an NLG system based on a Genetic Algorithm.