A platform-independent process for data retrieval from ontology-oriented data systems over computer networks through a flexible system and method of query paraphrasing. The present invention uses a “common ontology” that is not tied to any particular data system. Thus, each client computer issues queries to a target data system in the common ontology. Of course, the target data system will not be able to directly process the query (as it is not in its local ontology). Instead, the query is first paraphrased back from the common ontology into local ontology by taking the semantic query, passing it through a query paraphraser, and then sending the paraphrased query to the data system. Once it is paraphrased successfully, the target data system can process it and produce a result using local ontology. The result may then be sent from the data system to an answer paraphraser for paraphrasing, and the paraphrased answer may be returned to its original query issuer and on to the client.