Sadly, the “speech banana” isn’t a super fruit that improves hearing or is a reference to that old comic skit that goes, “Speak up…I can’t hear you…I’ve got a banana in my ear.” The thing that the “speech banana” refers to is a special pattern found in the results of an audiogram, which is a graphical representation of someone’s hearing proficiency within a set range of frequencies and volume levels. Audiograms are graphs of frequency (on the horizontal axis) and loudness (on the y axis). During a hearing test, each test sound is characterized by its frequency and volume and can be plotted on a chart.
When the common sounds of human speech – or phonemes – are graphed on such an audiogram, they have a tendency to all cluster within an area of the chart that is in the shape of a banana. The spoken sound of all of the letters in the alphabet, aside from q, w, x, and y, cluster inside the speech banana, as do the very widespread letter pairs ng, ch, sh and th.
The speech banana is extremely important because it encompasses nearly all of the sounds of human speech which is vital for our communications with one another. People with normal hearing, can hear many sounds outside the banana such as high frequency birds chirping or low frequency tubas. It is quite common for people to have difficulty hearing or understanding letter combinations such as ng, th, sh and ch and certain vowels.
Consequently, hearing professionals are most focused on hearing impairment that occurs within the range of the speech banana. If you’re having issues hearing sounds inside this range, whether you are old or young, you are probably having difficulty hearing people properly, and may encounter problems conversing with them.
The array of spoken sounds encompassed by the speech banana is so essential to communications, that a number of school districts require hearing tests using audiograms to identify hearing losses in this region. Because this frequency and volume range of sounds is so essential to communications it is the range that most hearing aids are programmed and tuned for. If you have any concerns about your hearing in the speech banana range feel free to call and ask us about it.