Increasingly sophisticated technology that detects nuances in sound inaudible to humans is capturing clues about people’s likely locations, medical conditions and even physical features.Law-enforcement agencies are turning to those clues from the human voice to help sketch the faces of suspects. Banks are using them to catch scammers trying to imitate their customers on the phone, and doctors are using such data to detect the onset of dementia or depression.  That has… raised fresh privacy concerns, as consumers’ biometric data is harnessed in novel ways.

“People have known that voice carries information for centuries,” said Rita Singh, a voice and machine-learning researcher at Carnegie Mellon University who receives funding from the Department of Homeland Security…Ms. Singh measures dozens of voice-quality features—such as raspiness or tremor—that relate to the inside of a person’s vocal tract and how an individual voice is produced. She detects so-called microvolumes of air that help create the sound waves that make up the human voice. The way they resonate in the vocal tract, along with other voice characteristics, provides clues on a person’s skull structure, height, weight and physical surroundings, she said.

Nuance’s voice-biometric and recognition software is designed to detect the gender, age and linguistic background of callers and whether a voice is synthetic or recorded. It helped one bank determine that a single person was responsible for tens of millions of dollars of theft, or 18% of the fraud the firm encountered in a year, said Brett Beranek, general manager of Nuance’s security and biometrics business.

Audio data from customer-service calls is also combined with information on how consumers typically interact with mobile apps and devices, said Howard Edelstein, chairman of behavioral biometric company Biocatch. The company can detect the cadence and pressure of swipes and taps on a smartphone.  How a person holds a smartphone gives clues about their age, for example, allowing a financial firm to compare the age of the normal account user to the age of the caller…

If such data collected by a company were improperly sold or hacked, some fear recovering from identity theft could be even harder because physical features are innate and irreplaceable.

Sarah Krouse, What Your Voice Reveals About You, WSJ, Aug. 13, 2019