Vocal Behavior of Teachers Reading with Raised Voice in a Noisy Environment

Abstract

(1) Objective: Teaching is a particularly voice-demanding occupation. Voice training provided during teachers' education is often insufficient and thus teachers are at risk of developing voice disorders. Vocal demands during teaching are not only characterized by speaking for long durations but also by speaking in noisy environments. This provokes the so-called Lombard effect, which intuitively leads to an increase in voice intensity, pitch and phonation time in laboratory studies. However, this effect has not been thoroughly investigated in realistic teaching scenarios. (2) Methods: This study thus examined how 13 experienced, but vocally untrained, teachers behaved when reading in a noisy compared to quiet background environment. The quiet and noisy conditions were provided by a live audience either listening quietly or making noise by talking to each other. By using a portable voice accumulator, the fundamental frequency, sound pressure level of the voice and the noise as well as the phonation time were recorded in both conditions. (3) Results: The results showed that the teachers mainly responded according to the Lombard effect. In addition, analysis of phonation time revealed that they failed to increase inhalation time and appeared to lose articulation through the shortening of voiceless consonants in the noisy condition. (4) Conclusions: The teachers demonstrated vocally demanding behavior when speaking in the noisy condition, which can lead to vocal fatigue and cause dysphonia. The findings underline the necessity for specific voice training in teachers' education, and the content of such training is discussed in light of the results.

Keywords: Lombard effect; phonation time; teachers’ voice; vocal health.

Figure 1

Increase in the phonation time of the voice showed a significant correlation with increases in sound pressure level (SPL) of the voice but not the noise. The figure displays differences in the voice SPL (orange) and the noise SPL (blue) between the conditions against the difference of the phonation time.

Figure 2

Significant increase in duration of phonation from quiet to noisy condition with stable duration of inhalations. The figure displays Mean durations of the voicing and the pauses (>200 ms) between conditions (error bars: standard error of the mean; *: p < 0.01).