The new device, developed by researchers at Baylor College of Medicine in Houston, Texas, relies on sensory substitution, which involves feeding information from one sense into another.
The device, known as versatile extra-sensory transducer (VEST), can be worn on top of clothing or underneath, LiveScience reported.
A microphone on the vest captures sounds from the environment and feeds them into an Android tablet or smartphone, which extracts the audio relevant to speech and converts it into unique patterns of vibration in about two dozen tiny buzzers.
In each trial, the vest would vibrate in a pattern corresponding to a randomly chosen word, and the wearer had to guess the correct word from a set of four choices.
They compared two different algorithms for translating words into vibration.
The participants performed between 300 and 600 trials once per day, either until they got more than 75 per cent of the words correct, or for a 12-day period.