Your voice is distinctive , depending on your physical makeup and the language you speak.  The latest machines can tease apart the most minute differences, although changes in a voice owing to a cold or a stressful situation can confuse the listening machine.

The  latest version of Apple’s operating system learns what your voice sounds like and can identify you when you speak to Siri, ignoring other voices that try to intervene.   Voice-identification systems have started to creep into everyday life, from smartphones to police stations to bank call centres. Google has recently unveiled an artificial neural network that can verify the identity of a speaker saying “OK Google” with an error rate of 2 per cent.

For machines, recognising individual voices is different from understanding what they are saying. The recognition software has been fuelled by massive sets of vocal data built into a huge model of how people speak. This allows measurements of how much a person’s voice deviates from that of the overall population, which is the key to verifying a person’s identity.

I have reservations about some tech innovations, but this seems to be a good one. The technology is already being used in criminal investigations. Last year, when journalist James Foley was beheaded, apparently by ISIS, police used it to compare the killer’s voice with that of a list of possible suspects. And the banks JP Morgan and Wells Fargo have reported started using voice biometrics to figure out whether people calling their helplines are scam artists.   A voiceprint gives insight into the speaker’s height and weight, their demographic background, and even what their environment is like. It may soon be possible to detect a person’s likely diseases or psychological state through voice analysis. (Aviva Rutkin, New Scientist, Oct 2015)

Where one can draw the line is if these machines can understand (and report on?) what you are saying, which an altogether different proposition.  Samsung designed their smart TVs to record private conversations.  Now why should they do that?  This looks like another weapon to be potentially used by secret services, foreign hackers  and crooks.