Listening can tell you what you heard. It cannot reliably prove who spoke.
Modern speech synthesis can reproduce a person’s voice from recordings. A call may also be compressed, noisy, or interrupted, which makes small audio details hard to judge. A pause, an odd word, or a smooth delivery may raise a question; none is a dependable test of identity.
Two research studies illustrate the limit. Barrington, Cooper, and Farid tested cloned voices based on 220 speakers with 604 listeners. Participants did not consistently identify the clones. The researchers used one voice-cloning service and a U.S. English-speaking sample, so the result is not a score for every model, language, or real-world call. A separate 1,276-person study across synthetic images, audio, video, and audiovisual clips found that people struggled to distinguish synthetic from authentic media by perception alone.
The practical conclusion is narrow: do not make a high-stakes decision from how a voice feels. Verify the identity and the request independently.
