An interactive response system mixes HSR subsystems with ASR subsystems to facilitate overall capability of voice user interfaces. The system permits imperfect ASR subsystems to nonetheless relieve burden on HSR subsystems. An ASR proxy is used to implement an IVR system, and the proxy decides, based on a set of rules, to route an utterance solely to one ASR, to route it to an HSR in addition to at least one ASR, to route it solely to one or more HSR subsystem, to reroute an utterance originally sent to an ASR over to an HSR, to use HSRs to help tune and train one or more ASRs, and to use multiple ASRs to increase reliability of results.