Dear School Administrator:

Did you know that, if classrooms in your school are typical of those in the U.S., the noise level may jeopardize student learning and threaten the vocal health of your teachers?

• Noisy and overly reverberant classrooms only allow students to understand about three out of four words their teachers speak, according to an analysis from the University of Kansas. Other investigators have found that as many as half of the students cannot hear past the first two rows of the classroom. Imagine how teacher intelligibility drops for a student with either temporary hearing loss (common middle ear infection) or permanent hearing loss or a learning problem?
• It is more critical for children than adults to receive clear messages from a speaker. With their limited language experience, if young children miss a few of their teachers' words, they are less able to fill in the gaps and make sense of their teachers' communication.
• The American National Standards Institute recommends 35 decibels as an acceptable noise level in an empty classroom. This is approximately equal to a quiet living room. Unfortunately, most American classrooms have a sound level of 45 decibels or more.
• All too many teachers are trying to make up for these acoustic shortfalls by speaking louder than the interfering noise. This — coupled with the high professional demand for speaking — creates a serious vocal health hazard for many teachers.

In response to concerns about the vocal health of teachers, we've built the Voice Academy, a project sponsored by the National Institute on Deafness and Other Communication Disorders, a division of the National Institutes of Health. This website is available at http://www.voiceacademy.org.

Two of the rooms in the virtual Voice Academy represent the best- and worst-possible acoustic classroom conditions. In short, acoustical friendliness can almost always be achieved by reducing sound reflections and lowering background noise.

You would not be in your profession if you weren't committed to creating the best possible learning environment for your students. Awareness is a great initial step. Suggestions for improving classroom acoustics — along with general information about costs — are included on the Voice Academy website. If the information is not attached to this letter, you may retrieve it on the Internet at http://www.voiceacademy.org/acousticfixes.html.

If you'd like to explore this topic in more detail, we suggest an on-line booklet prepared by the Acoustical Society of America. It is available without cost on the organization's website http://asa.aip.org/classroom/booklet.html.

Sincerely,

Julie Ostrem, BS, MBA, Project Director, Voice Academy
Ingo Titze, PhD, Director, National Center for Voice and Speech