Mean F0 values obtained through standard phrase pronunciation compared with values obtained from the normal work environment: a study on teacher and child voices performed in a preschool environment.

Mean fundamental frequency (F(0)) values are often used in research on vocal load. In this study, we examine how the mean F(0) differs when evaluated through pronouncing a standard phrase as compared to the mean F(0) obtained in a real work/play environment. We also examine how the F(0) values change throughout the day. The study was performed in a preschool, nine adult female preschool teachers and 11 children participated. The participants wore a digital recorder equipped with an accelerometer, which was attached to the neck. In the study, the participant first pronounced a standard phrase in a controlled environment; thereafter, the voice was recorded in the environment where both children and adults normally reside throughout the day, denoted by the work/play environment. For each participant, the procedure was repeated four times throughout the day. Analyses showed that the F(0) values of the children's and adult's voices were significantly higher when recorded in the work/play environment as compared to the controlled environment. The average difference was 36 Hz for adults and 24 Hz for children. Previous studies have shown an increase of F(0) over the day for teachers. In this study, an increase between morning and afternoon values was found amounting to 8 Hz for adults and 24 Hz for children. For the child population, this increase was statistically significant. However, the total changes over the day revealed a somewhat more complex scheme, with an increase of F(0) in the morning, a decrease during lunch, and finally an increase in the afternoon. This pattern was verified statistically for the joint child-adult population.