Vocal fatigue is a voice symptom which is frequently reported by professional voice users. teachers, singers, actors and other professions that require prolonged voice use are especially at-risk group. the vocal fatigue results in auditory perceptual and acoustic changes in the voice signal and can lead to serious pathological conditions. the present study has examined acoustic manifestations of the vocal fatigue in pronunciation teachers who seem to be particularly susceptible vocal and articulatory fatigue. in the paper detailed acoustic analysis of the data obtained is presented. the results of the acoustic analysis showed a consistent dependency between acoustic parameters and vocal fatigue. © 2011 Firenze University Press.