Speech Perception


The aviation industry would not operate if it were not for communication. Language, speaking and speech perception play a fundamental role in aviation operations. Pilots communicate verbally with ATC and vice versa. Aircrew speak with each other during flight etc. The way we perceive a word can have a large effect on the message we receive, independent of whether that was the exact message intended from the speaker.
To perceive a word, our brain must differentiate the word's sound pattern that is receives from tens of thousands in its memory. The sound distinguished must be separated from the memory's irrelevant words and must also be isolated from other ambient noise around the person. Accurately perceiving someones speech is a complex task that we often do with ease, however in aviation, errors in speech perception can lead to accidents or incidents.

Definitions of Speech Perception

  • Our mind receiving raw sound data, recognizing that it is speech and then associating meaning to the received speech.
  • Our auditory system recording the sound vibrations generated by someone talking, then the system must translate these vibrations into a sequence of sounds that you perceive to be speech. (Matlin, 20091).
  • "The process of imposing a meaningful perceptual experience on an otherwise meaningless speech input" (Massaro, 20012)
  • "The process by which the sounds of language are heard, interpreted and understood." (Wiki, 20123)
Psycholinguistics - Speech Perception
(Video embedded from YouTube on 21 August 2012)

Roles in Aviation

The study of speech perception can be useful in aviation. Studying the way people perceive speech can shed light on certain sources of errors in communication. This can then be used to make improvements in the way operators communicate with each other. For instance, using simple clear spoken words to convey a message would be better than relying on emphasis on words or more emotive tones, as these are more easily perceived in difference ways by different people. Words have given definitions and are therefor less likely to be perceived incorrectly.
The research of speech perception could have applications for cockpits through the use of speech recognition. Many computers and machines are now becoming equipped with the capabilities of speech recognition, e.g. cell phones, telephone answer machines, personal computers etc. These systems need to be programmed to perceive and recognized the words directed at them. If the technology becomes accurate and reliable enough cockpits may adopt this technology more so in the future which could allow pilots to make adjustments to controls or displays simply through using their voice.

Speech leading to Accidents

If speech is perceived incorrectly then a message may not be conveyed as intended. While this may not normally be a big deal or mean catastrophe, in aviation in certain situations with critical messages being communicated, or high pressure situations, accurately perceiving speech is very important. A well known example of miss-communication is a captain requesting "take-off power" during take off and the co-pilot reducing thrust as he perceived the command as "take off power".

Matlin (20091) used the accident at the Canary Islands as an example of speech perception playing a role in an accident. In 1977 at Tenerife airport the lives of 538 people were tragically lost. Two 747's collided on the runway due in part to poor visibility, but largely due to a communication error between a pilot taking off and an air traffic controller. Voice was the only form of communication at the pilots and ATC's disposal due to fog covering the airfield. Poor audio transmission and miss-communication were largely responsible for the accidents occurrence. The crash lead to increased emphasis placed on using standardized phraseology in ATC communication by both controllers and pilots alike, thereby reducing the chance for misunderstandings (Wiki, 20125).


Pronunciation is perhaps one of the biggest issues when considering clear accurate communication and speech perception. As English is the international aviation language many people are required to learn it as a second language which can lead to very noticeable varying accents. The location of which a person has resided also can influence their accents. These accents often alter the way words are pronounced which can reduce a listeners accuracy of perception. If different parts of a word are stressed or a speaker uses a different rhythm or intonation it can sound quite different. Ideally to reduce potential miss-communication extreme accents and pronunciation differences should be altered and reduced if possible.

Improving Speech

In order to increase the chances of your message being accurately perceived by a listener there are several things that can be done.

  • Control your tone and volume; Do not shout or swear. Loud volumes can distort over radio and shouting is not help convey a message clearly
  • Avoid stuttering or mumbling; Communications should be clear and concise
  • Keep a reasonable pace; Voice that is too slow or too fast can hinder the listeners perception of what is being said.
1. Matlin, M. W. (2009). Cognition. Hoboken, NJ, USA: John Wiley & Sons, Inc.
2. Massaro, D. W. (2001). Speech Perception. International Encyclopedia of Social and Behavioral Sciences. (pp. 14870-14875). Amsterdam, The Netherlands: Elsevier
3. Wikipedia. (2012). Speech Perception. Retrieved 16 August 2012, from: http://en.wikipedia.org/wiki/Speech_perception
4. Wickens, C. D., Hollands. J. G. (2000). Energineering Psychology and Human Performance (3rd Ed.) Upper Saddle River, New Jersey 07458
5. Wikipedia. (2012). Tenerife airport disaster. Retrieved 16 August 2012, from: http://en.wikipedia.org/wiki/Tenerife_airport_disaster

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