19. The system of claim 18 , wherein the one or more modules are further configured to: store in the memory the word that is associated with the concept.
18. A system, comprising: one or more processors; and memory, communicatively coupled to the one or more processors, storing one or more modules configured to: electronically receive a natural language input phrase from an interface device; attribute a concept to the natural language input phrase, wherein the concept is a breakdown of one or more ideas in the input phrase and the attributing is based at least in part on a pattern among terms in the natural language input phrase; associate a word in the natural language input phrase with the concept; search a database of a set of documents to identify one or more documents associated with the attributed concept to be included in a response to the natural language input phrase; maintain the concept during an interactive session between the natural language processor and the interface device; receive an ambiguous natural language input phrase during the interactive session; and determine that the ambiguous natural language input phrase has a same meaning as the word that is associated with the concept.