Methods, systems and computer readable media for finding documents in a data store that match a natural language query submitted by a user are provided. The documents and queries are matched by determining that words within the query have the same relationship to each other as the same words in the document. Documents are semantically analyzed and words in the document are indexed along with the role the word plays in a sentence. The initial semantic role may be generalized using a role hierarchy and stored in the index along with the original role. A similar analysis may be used with the search query to find words used in the same role in both the query and the document.