A voicemail system that labels messages according to the caller’s tone of voice could soon be helping people identify which messages are the most urgent.

The software, called Emotive Alert, works by extracting the distribution of volume, pitch and speech rate – the ratio of words to pauses – in the first 10 seconds of each message, and then comparing them with eight stored “acoustical fingerprints” that roughly represent eight emotional states: urgent or not urgent; formal or informal; happy or sad; excited or calm.

The fingerprints were created by “learning” software, which was fed hundreds of snippets from old voicemail messages that had been assigned emotional labels by the researchers.