Human voice intonation is affected by pitch and loudness. Pitch is related to the frequency of human
voice, while Loudness is related to the magnitude of human voice. Someone who does not have vocal
cords, He has no ability to produce voice and speech. This problem is suffered by laryngectomy
patients. Over half of all laryngectomy patients worldwide are using electrolarynx for the
rehabilitation of their speech ability. Unfortunately, the electrolarynx voice is monotonic and flatted
intonation. Small changes in pitch and loudness of electrolarynx will give a better expression in
laryngectomy patients. Previous researches have focused on utilization of Electromyography (EMG)
signal of neck muscle for only pitch control. In this research, the relationship between human voice
intonation (i.e., frequency and magnitude) and EMG signals of neck muscles was studied by looking
for their correlation and their mutual information. Human voice signal and EMG signal of neck
muscle were recorded simultaneuosly while subjects were saying “A” with varying intonation. The
EMG signal of neck muscle was processed using amplifying, filtering, rectifying and “moving
average” process. On the other hand, the human voice was processed by FFT Algorithm to obtain
magnitude and fundamental frequency. The result shows that the correlation coefficient between
human voice magnitudes and EMG signal of neck muscle is 0.93, while the correlation coefficient
between human voice frequency and EMG signal of neck muscle is 0.88. Moreover, the mutual
information between human voice magnitudes and EMG signal of neck muscle is 1.07, while the
mutual information between human voice frequency and EMG signal of neck muscle is 0.65. These
results show that the relationship between human voice magnitudes and EMG signal of neck muscle is
stronger than the relationship between human voice frequencies and EMG signal of neck muscle.
Therefore, it is more appropriate to use the EMG signal of neck muscle for controlling loudness of
electrolarynx than that of the pitch of electrolarynx