Updated: May 12, 2020
When we think about listening, whether this is to a teacher’s voice in class or other environmental sounds such as a car or birdsong, we don’t often consider the complexities involved in this seemingly simple process.
There are only four areas we need to think about when we consider basic auditory processing.
Frequency - Pitch of the sound
Amplitude - How loud or soft is the sound
Space - Where is the sound coming from
Time - How long does it last
This blog is specifically about frequency of speech sounds.
All natural sound, including your own voice, is a complex mix of frequencies that need to be processed to be understood. For speech, the mix of frequencies is really important to understand not just the words, but also the emotional content; is someone happy or angry? Your ear and brain need to be able to track the quickly changing frequencies to gain any understanding of what is being said and work out what response is appropriate. Think of even listening to a word like ‘cat’. Here is the word mapped out visually using spectral analysis…
In the picture above, the frequency or pitch is on the vertical axis with time on the horizontal axis. The first burst of colour is the word ‘cat’ at normal speed. The second is the word ‘cat’ with the ‘a’ lengthened. The separate sounds or phonemes of ‘c’, ‘a’ and ‘t’ are at different frequencies and you can see the ‘t’ comes after a tiny gap in sound. All the red colour represents the highest volume of low frequency sound in the vowel ‘a’.
It has been found in research (Sun et al, 2017) that “accurate pitch discrimination is critical to phonological processing”. This is the ability to listen to and manipulate the units of sound that make up letters and words.
Going back to our ‘cat’ we find that the ‘t’ sound is at a much higher frequency, around 6000Hz, than the ‘a’ which is at perhaps 600Hz. To process sound at a basic level we need to process these fast changes in pitch in milliseconds.
It is well understood that people with auditory processing problems as well as in Dyslexia, Autism and other labels have challenges in this area. Research shows that children with autism have difficulties tracking pitch (Otto-Meyer et al, 2019) and so do children with Dyslexia (Ziegler et al, 2011).
It is clear then that if we have difficulties with processing the quickly changing frequencies in speech, we can have challenges with listening, speech and reading. If we cannot process speech quickly enough, this will often lead to social issues as we simply are unable to keep up with our peers.
Music can really help here. The brain needs to learn and develop the ability to process frequency whether it is produced by an instrument or through speech – the fundamentals are the same. Learning an instrument or singing in a choir can develop auditory processing skills. Particularly good would be stringed instruments such as a violin or cello where you need to place your fingers in a very specific place on the string to produce the exact note. Brass and reed instruments such as the trombone or clarinet also require adjustments of the lips and breath to find the correct pitch.
There are also more therapeutically based (and often easier!) options. The Listening Program (TLP) was developed specifically to help anyone with this type of developmental delay to retrain the auditory system. TLP breaks down the frequency range into specific bands to allow for a subtle retraining of the auditory system.
Frequency or pitch perception can be improved and should be a key component of a programme for children with auditory processing problems, Dyslexia, Autism and other labels. This can help build the foundations of listening, attention and speech.
Alan Heath is the Director of Learning Solutions and International Representative for Advanced Brain Technologies.
Otto-Meyer, S., Krizman, J., White‑Schwoch, T. and Kraus, N. (2018) Children with autism spectrum disorder have unstable neural responses to sound. Experimental Brain Research. Vol 236. Pp733-743. https://doi.org/10.1007/s00221-017-5164-4
Sun, Y., Lu, X., Ho, H, T. and Thompson, W. F. (2017) Pitch discrimination associated with phonological awareness: Evidence from congenital amusia. Scientific Reports| 7:44285 | https://doi.org/10.1038/srep44285
Ziegler, J. C., Pech-Georgel, C., George, F. and Foxton, J,M. (2012) Global and local pitch perception in children with developmental dyslexia. Brain & Language.Vol 120 (3) pp. 265-270. https://doi.org/10.1016/j.bandl.2011.12.002