Voice Prints
Seems that it’s hard:
“There is no such thing as a voice print,” he said. “It’s a very very dangerous term. There is no single feature of a voice that is indelible that works like a fingerprint does.”
Many different factors influence how people speak at any particular time and place.
“If you’re tired or if you have a cold or if you’re speaking on a phone against traffic in the background you do all sorts of things to the voice, which make it phonetically very different from time to time,” said Foukles, who also works as a freelance consultant for a private forensic speech science laboratory.
“The features of speech and language are such that you can’t use them as a marker of identity to identify one person and exclude all other people under normal circumstances. People’s voices overlap.”
Pete Austin • December 23, 2008 7:52 AM
Recognizing voices is hard, as Sarah Palin’s team learned.
http://news.bbc.co.uk/1/hi/world/americas/us_elections_2008/7704666.stm
Also “for example Queen Elizabeth II, who was fooled by Canadian DJ Pierre Brassard posing as Canadian Prime Minister Jean Chrétien, asking her to record a speech in support of Canadian unity ahead of the 1995 Quebec referendum. Two other particularly famous examples of prank calls were made by the Miami-based radio station Radio El Zol. In one, they telephoned Venezuelan president Hugo Chávez and spoke to him, pretending to be Cuban dictator Fidel Castro. They later reversed the prank, calling Castro and pretending to be Chávez. Castro began swearing at the pranksters live on air after they revealed themselves”
http://en.wikipedia.org/wiki/Prank_call