1. A digital data processing apparatus for information retrieval, said apparatus comprising A. input means for accepting a signal representative of a search linguistic expression in conventional textual reoresentation. B database storage means for storing signals representative of plural textual expressions and information pertaining thereto, C. database matching means in circuit with said input means and with said database storage means for locating within said database a linguistic expression matching or similar to said search linguistic expression, said database matching means including skeletonization means for converting at least one said database linguistic expression to a linguistically salient word skeleton, and for converting said search linguistic expression, or a modified form thereof, to a linguistically salient word skeleton, said converting means comprising i. means for eliminating from the word skeleton produced thereby a selected alpha set, if any, of the expression being converted which lacks isomorphy with a phonetic representation of that selected set, and ii means for replacing with a different linguistic symbol another selected alpha set, if any, of the expression being converted which lacks isomorphy with a phonetic representation of that other selected set, D. output means in circuit with said matching means for generating a signal indicative of the success of locating at least one database linguistic expression matching or similar to said search linguistic expression and for generating signals representative of information pertaining to the matching or similar database linguistic expressions, if any.