Voice biometrics are numerical models of characteristics (like the sound, pattern, and rhythm) within an individual’s voice, and are represented in a voiceprint of spoken qualities.Click the link for the answer in a really good and concise post about voice biometrics. I'd also encourage you to check out other content at IVR Deconstructed, especially posts by Lisa, for even more thoughtful material on voice biometrics, privacy and logical access control.
The technology often acts as a quick, convenient, and secure method of remotely determining an individual’s identity. So why haven’t more organizations integrated these functionalities into their IVR systems?
In case you're wondering, IVR stands for Interactive Voice Response. I have a name for the IVR technology used by call centers: The Robot Lady. You may also know it as the beast that can only be slain by frantically and repeatedly pressing zero.
See also: Voice Biometrics and ID Management in Call Centers