“Speech bananas” aren’t mid-day snacks for audiologists.What the “speech banana” refers to is a special pattern shown in the data of an audiogram, which is a graphical representation of an individual’s hearing acuity inside a set range of volume levels and frequencies. Audiograms are plots of sound frequency (on the horizontal axis) and decibels (on the y axis). During a hearing evaluation, each test sound is defined by its volume and frequency and can be graphed to create a chart.
When the standard sounds of human speech – or phonemes – are plotted on such an audiogram, they tend to all cluster within an region of the graph that is shaped like a banana. Nearly the whole alphabet and the majority of letter combinations (such as ch, sh, th and ng) cluster into the speech banana range on an audiogram. The primary exceptions are the letters q, w, x, and y.
People with normal hearing can also hear sounds that fall outside this speech banana range – which includes higher-frequency sounds such as a glass breaking or a mosquito and lower-frequency sounds such as a fog horn or thunder – but the sounds most vital to human communication are the sounds of people speaking. Individuals with hearing problems often have difficulty hearing specific vowels and the letter combinations th, ch, sh, and ng.
When hearing impairment impacts the volumes and frequencies inside the speech banana it disrupts person-to-person communications. For this reason audiologists will often concentrate on that area. Irrespective of whether the individual is old or young, if they’re having difficulty hearing sounds within that frequency and volume range, they are almost definitively having difficulty hearing speech, and thus have problems communicating properly with others.
The speech banana is regarded as so important to hearing health that many schools have mandated audiograms for their students in order to detect and address hearing problems early that may be impacting their ability to communicate. The significance of this special range of sounds is an additional reason why hearing aids need to be properly tuned and adjusted by a professional hearing instrument specialist or audiologist, to make sure you can hear the sounds of speech clearly.Be sure that you don’t miss any of the human speech in your daily life by getting a hearing test and audiogram if you think you may have a problem.