1. A method, comprising: electronically receiving, by a computer-implemented natural language processor, a natural language input phrase from an interface device during an interactive session; attributing, by the natural language processor, a concept to the natural language input phrase, wherein the concept is a breakdown of one or more ideas in the natural language input phrase and the attributing is based at least in part on determining a pattern among terms in the natural language input phrase; associating a word in the natural language input phrase with the concept; searching a database, by the natural language processor, for 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; causing the response to be provided to a user, the response including the one or more identified documents associated with the attributed concept; maintaining, by the natural language processor, the concept during the interactive session between the natural language processor and the interface device; receiving another natural language input phrase during the interactive session; and determining that one or more ambiguous words in the another natural language input phrase correspond to the word that is associated with the concept.