REFERENCE IDENTIFICATION AND REFERENCE IDENTIFICATION FAILURES 
 
 The goal of this work is the enrichment of human-machine interactions in a natural language environment . Because a speaker and listener cannot be assured to have the same beliefs , contexts , perceptions , backgrounds , or goals , at each point in a conversation , difficulties and mistakes arise when a listener interprets a speaker's utterance . These mistakes can lead to various kinds of misunderstandings between speaker and listener , including reference failures or failure to understand the speaker's intention . We call these misunderstandings miscommunication . Such mistakes can slow, and possibly break down, communication . Our goal is to recognize and isolate such miscommunications and circumvent them. This paper highlights a particular class of miscommunication --- reference problems --- by describing a case study and techniques for avoiding failures of reference . We want to illustrate a framework less restrictive than earlier ones by allowing a speaker leeway in forming an utterance about a task and in determining the conversational vehicle to deliver it. The paper also promotes a new view for extensional reference . 