Improvement of electrolaryngeal speech by introducing normal excitation information

In electrolaryngeal speech, an excitation signal is provided by means of a buzzer held against the neck which is usually operated at a constant frequency rate. While such Transcutaneous Artificial Larynges (TALs) provide a means for verbal communication for people who are unable to use their own, the monotone F0 pattern results in poor speech quality. In the present study, cepstral analysis was used to replace the original F0 contour of the TAL speech with a normal F0 pattern. Spectral analysis shows that this substitution results in two changes: (a) a varying F0 contour and (b) removal of steady background noise due to the leakage of acoustic energy. Perceptual tests were conducted to assess speech, before and after cepstral processing, produced by four laryngectomized speakers (2 males and 2 females). All speakers used the Servox TAL. The results indicate a clear preference for the processed speech.