PSST! Did you hear the news? A new program can convert whispers into normal-sounding speech.
Whispering is useful if you don鈥檛 want to be overheard, but it鈥檚 also unavoidable if your vocal cords are damaged. So an app that turns whispered words into full speech could be invaluable.
One hurdle is that whispering cannot produce all the tones achieved by our vocal cords. That missing ingredient means it doesn鈥檛 have an actual pitch.
Advertisement
Any app that miscalculates the pitch can muddle the message. In English, pitch makes the difference between sounding earnest and sarcastic. In Japanese, it changes the meaning of words, for example turning 鈥済ood鈥� into 鈥渄runkenness鈥�.
For this reason, whisperers instinctively try to indicate the pitch in other ways, for example by changing the shape of their mouth, helping listeners guess the intended pitch.
鈥淎 miscalculated pitch can muddle the message. It can change the Japanese word 鈥榞ood鈥� to 鈥榙runkenness鈥欌��
Hideaki Konno and his colleagues at Hokkaido University of Education in Japan played sounds with just one frequency to five people and asked them to whisper at those pitches. This established a link between their whispers and intended pitch (Speech Communication, ).
From that, the team built a pitch predictor. The algorithm analysed whispered Japanese words for which pitch changes meaning, then added the missing frequency. Eight people who listened to the synthesised words grasped the intended meaning 72 per cent of the time.
Such a system could eventually run on a smartphone, says Konno. But for that to happen, the algorithm must become good enough to reconstruct complete sentences.
This article appeared in print under the headline 鈥淲hisper tech turns secrets into normal speech鈥�
