The Variability Problem

The variability problem is a speech related issue that arises between auditory signals (acoustic signals) and the actual sounds we hear, which can cause confusion in our comprehension of the sound information (Goldstein, 2010). Such occurrences are commonplace, and everyone has a story about what they could have sworn you said. But why does this occur?

The basis of this problem is the acoustic signal, a signal produced by air that is produced by the vocal cords and vocal tract by air being pushed up through them (Oberman, N.d). These signals consist of phoneme, the smallest unit of speech that will change the meaning of a word. For example, the English alphabet contains 47 phonemes (13 major vowel sounds, and 24 major consonant sounds) (Oberman, N.d). Keeping this in mind, the variability problem describes how a change in spoken sound (acoustic sound) can change the meaning of the word, and even cause misunderstanding about the meaning of the phrase or word.

The first variability issue can arise from context and coarticulation. Context and coarticulation refers to the pitch at which a particular phoneme is pronounced when followed another phoneme. For example, although we understand "t" to always be a "t," it sounds differently when followed by different letters. Think of the "t" in the word "task" and compare it to the word "mint." The "t" no longer sounds the same, because in word one we're coupling it with an "a" in "task," but with a "n" in "mint."

The second factor creating variability in our understanding of sounds in speech derives from the person speaking (Goldstein, 2010). For example, think about when you hear an Australian accent versus an American accent. Do the "a's," and "o's" sound the same? How about someone with a Japanese accent? Are English words as clear to you? Often times we have trouble understanding people with different accents (at least at first) because we are unfamiliar with the sound of the phoneme they're pronouncing. But, how does this explain some of the misunderstandings that arise in other native English speakers? This could have to do with the sex of the individual speaking, at what speed they're speaking, the dialect, and the enunciation (University of Western Ontario, 2008).

References

Goldstein, E. B. (2010). Sensation and perception (8th ed.). Belmont, CA: Wadsworth

Oberman, L. (N.d). Speech Perception. Retrieved November 24, 2009, from http://psy2.ucsd.edu/~lshenk/Speech-Perception-Lecture2.pdf

University of Western Ontario. (2008). Speech Perception. Retrieved November 23, 2009, from https://instruct.uwo.ca/psychology/215b-570/notes/Mar28.pdf