Do speakers articulate over-described modifiers differently from modifiers that are required by context? Implications for models of reference production

Studies have shown that speakers often include unnecessary modifiers when producing referential expressions, which is contrary to the Maxim of Quantity. In this study, we examined the production of referring expressions (e.g. the red triangle) that contained an over-described (or redundant) pre-nominal adjective modifier. These expressions were compared to similar expressions that were uttered in a context that made the modifier necessary for unique referent identification. Our hypothesis was that speakers articulate over-described modifiers differently from those used to distinguish contrasting objects. Results showed that over-described modifiers were significantly shorter in duration than modifiers used to distinguish two objects. Conclusions focus on how these acoustic differences can be modelled by Natural Language Generation algorithms, such as the Incremental Algorithm, in combination with probabilistic prosodic reduction.