An interactive voice response unit which provides beneficial operation by including means to handle unconstrained input such as natural speech and to allow barge-in includes a prompter, a recognizer of speech signals, a meaningful phrase detector and classifier, and a turn-taking module, all under control...http://www.google.de/patents/US6246986?utm_source=gb-gplus-sharePatent US6246986 - User barge-in enablement in large vocabulary speech recognition systems
