A method for information retrieval that matches occurrences of concepts in natural language text documents against descriptions of concepts in user queries. Said method, implemented in a computer system, includes a preferred version of the method that comprises (1) annotating natural language text in documents and other text-forms with linguistic information and Concepts and Concept Rules expressed in a Concept Specification Language (CSL) for a particular domain, (2) pruning and optimizing synonyms for a particular domain, (3) defining and learning said CSL Concepts and Concept Rules, (4) checking user-defined descriptions of Concepts represented in CSL (including user queries), and (5) retrieval by matching said user-defined descriptions (and queries) against said annotated text. CSL is a language for expressing linguistically-based patterns. Said patterns can represent the linguistic manifestations of concepts in text. Said concepts may derive from the sublanguages used by experts to analyze specialized domains including, but not limited to, insurance claims, police incident reports medical reports, and aviation incident reports.