In a statistical study of 100 persons, 50 males and 50 females, aged from 22 to 26, the authors obtained the following data for parameters of aerodynamic studies as a part of estimation of vocal function : 1) Mean value of the maximum phonation time is 30.5 sec in men and 19.1 sec in women and the critical region is below 14.8 sec in men and below 12.1 sec in women. 2) Mean value of the vital capacity is 4,190 ml in men and 2,590 ml in women and the critical region is below 3,101 ml in men and below 1,885 ml in women. 3) Mean value of the phonation quotient is below 148 ml/sec in men and 133 ml/sec in women and the critical region is above 216 ml/sec in men and above 179 ml/sec in women. 4) Mean value of mean flow rate is 130 ml/sec in men and 118 ml/sec in women and the critical region is above 195 ml/sec in men and above 153 ml/sec in women.