Why Your Classroom Is Making You Hoarse
By the third week of September, a predictable thing happens. Teachers who ended June with a normal voice are hoarse by Thursday afternoon. Most of them assume they are doing something wrong: talking too much, not drinking enough water, getting older.
The more accurate explanation is usually the room.
Why do teachers lose their voices and get hoarse?
In a study of 2,401 participants, teachers reported a significantly higher lifetime prevalence of voice disorders than non-teachers.¹ The companion analysis found that teachers had missed more workdays over the preceding year because of voice problems and were more likely to be considering a change of occupation.²
Your room is setting your volume, not you
When background noise rises, talkers involuntarily raise vocal level. This is the Lombard effect, characterized in detail more than fifty years ago, and the critical word is involuntary.³ It is a reflex, not a choice, which is why "just remember to speak more quietly" fails as advice.
The relationship has been quantified in real classrooms. In a study of 40 primary school teachers across six schools, researchers measured a 0.72 dB increase in speech level for every 1 dB increase in background noise during traditional lessons, along with a rise in fundamental frequency of about 1.0 Hz per decibel.⁴ You are not only getting louder in a noisy room. You are getting higher, which loads your voice more.
The threshold is lower than most people expect. Work quantifying where the effect begins identified a change point at a background noise level of about 43 dB(A).⁵ A classroom with an HVAC system running, thirty students, and hard surfaces clears that easily and stays there all day.
That same dosimetry study found teachers phonate roughly 26% of the working day.⁴ A quarter of every day is active voice use, at an intensity the room is choosing for you.
Amplification is treatment
Teachers often resist a personal amplifier because it feels like an admission of weakness, or like something that will make them look ridiculous.
A study of ten teachers measured sound pressure level during classroom instruction with and without sound-field FM amplification and found a significant 2.42 dB decrease in vocal SPL when amplification was in use.⁶ That is a meaningful reduction in vocal output for a device that requires no behavior change at all.
More importantly, amplification has been tested as an actual treatment. In a randomized clinical trial, 64 teachers with voice disorders were assigned to voice amplification, resonance therapy, or respiratory muscle training for six weeks. Only the amplification and resonance therapy groups showed significant reductions in Voice Handicap Index scores and voice severity self-ratings. On a post-treatment questionnaire, the amplification group reported significantly more overall voice improvement, greater vocal clarity, and greater ease of speaking and singing than the other two groups.⁷
A portable amplifier is not a workaround for a voice problem. In a controlled trial, it was the intervention teachers rated most highly.
What to change this month
Reduce what the room is doing to you before you try to change what you are doing:
Turn off noise sources you control.
Soft surfaces, curtains, rugs, and even fabric on the walls reduce reverberation, which reduces the noise floor you are competing against.
Position yourself so you are not projecting across the longest dimension of the room.
Get an amplifier, and use it from the first period rather than saving it for the days you are already hoarse.
Finally, treat persistent symptoms. Get evaluated to see if this is injury, which becomes irreversible over years of cumulative voice use. Symptoms that should trigger a stroboscopy with a laryngologist:
Hoarseness that lasts more than two to three weeks
pain with speaking
or a voice that no longer recovers over a weekend all warrant laryngeal examination.
Teachers frequently normalize symptoms that we would investigate immediately in a performer, and the tissue does not know the difference.
At the Center for Vocal Health, we care for educators alongside touring vocalists, because the vocal demands are more similar than most people assume, and the consequences of ignoring them are the same.
References
N. Roy, R. M. Merrill, S. Thibeault, R. A. Parsa, S. D. Gray, and E. M. Smith, "Prevalence of Voice Disorders in Teachers and the General Population," Journal of Speech, Language, and Hearing Research 47, no. 2 (2004): 281–293.
N. Roy, R. M. Merrill, S. Thibeault, S. D. Gray, and E. M. Smith, "Voice Disorders in Teachers and the General Population: Effects on Work Performance, Attendance, and Future Career Choices," Journal of Speech, Language, and Hearing Research 47, no. 3 (2004): 542–551.
H. Lane and B. Tranel, "The Lombard Sign and the Role of Hearing in Speech," Journal of Speech and Hearing Research 14, no. 4 (1971): 677–709.
P. Bottalico and A. Astolfi, "Investigations Into Vocal Doses and Parameters Pertaining to Primary School Teachers in Classrooms," The Journal of the Acoustical Society of America 131, no. 4 (2012): 2817–2827.
P. Bottalico, I. I. Passione, S. Graetzer, and E. J. Hunter, "Evaluation of the Starting Point of the Lombard Effect," Acta Acustica united with Acustica 103, no. 1 (2017): 169–172.
C. M. Sapienza, C. Crandell, and B. Curtis, "Effects of Sound-Field Frequency Modulation Amplification on Reducing Teachers' Sound Pressure Level in the Classroom," Journal of Voice 13, no. 3 (1999): 375–381.
N. Roy, B. Weinrich, S. D. Gray, K. Tanner, J. C. Stemple, and C. M. Sapienza, "Three Treatments for Teachers With Voice Disorders: A Randomized Clinical Trial," Journal of Speech, Language, and Hearing Research 46, no. 3 (2003): 670–688.
