Sadly, the “speech banana” isn’t a fruit that enhances hearing nor is it related to that old vaudeville comic skit that goes, “Speak up…I can’t hear you…I’ve got a banana in my ear.” The “speech banana” is a distinctive design depicted on an audiogram. Audiograms are typically graphed with the frequency level (measured in Hertz) on one axis and loudness level (measured in Decibels) on the y axis.
Exactly where the curious term originates from is the fact that when you review the sounds of human speech (called phonemes) on an audiogram, they have a tendency to cluster into a banana-shaped area of the graph. The spoken sound of all of the letters of the alphabet, except q, w, x, and y, fall within the speech banana, as do the common letter combinations ng, ch, sh and th.
The speech banana is important because it encompasses most of the sounds of human language which is vital for our ability to communicate with one another. Individuals with normal hearing, can hear lots of sounds outside of the speech banana such as low frequency tubas or high frequency birds chirping. Individuals with hearing problems frequently have difficulty hearing specific vowels and the letter combinations th, ch, sh, and ng.
Because of this, hearing specialist are most focused on hearing impairment that occurs within the range of the speech banana. If an audiogram shows that an individual has loss of hearing within the speech banana region, it is virtually certain that they are having communication difficulties.
The array of spoken sounds encompassed by the speech banana is so essential to communications, that many school districts require hearing assessments using audiograms to identify hearing impairments in this region. Since this frequency and volume range of sounds is so critical to human communications it is the range that most hearing aids are tuned and adjusted for. Irrespective of whether you presently wear hearing aids or not, give us a call if you have concerns about your hearing in the critical speech banana frequency and volume range.