As soon as I saw the chapter on speech I knew I wanted to do my mini report on speech and the perception of speech. In chapter 13, one of the first things addressed is something called PHONEME, that is basically the smallest unit of speech. However small, it is extremely important because it can change the meaning of a word. Since every language is different and has its out structure to it, the number of phonemes is not the small amongst all languages, each language actually varies in how many phonemes there is. The English language for example is known to have 47 of these phonemes which the notes tell us breaks down in 13 major vowel sounds and then 24 major consonant sounds.
Vowels are sounds in our language that are produced when the vocal cords vibrate making changes in the open shape of the vocal tract. The change in shape is what causes the change in resonant frequency and then produces a peak in the pressure. Consonants however, are the complete opposite because they are produced by the constriction of the vocal tract.
It was in 1886 that something called the International Phonetic Alphabet, which was used to represent all the sounds made by human speech. However this IPA was made off of the French language which uses an entirely different language structure from the English language. So the english language created the English Phonetic Alphabet in 2001. Which you could find here
What interested me most was the part on variability from different speakers because I myself have a lisp and some people can easily understand me, may even forget I have one ( if encountered enough like my full time coworkers, friends and family. If you were to ask any one of them they would say they heard it the first day they met me and then never again.) and some people just have a hard time understanding me, usually when I first introduce myself as Alex and I get "ALICE?" it is times like those I really struggle with my lisp.
I understand everyone differs in pitch, accent, speaking rate and their pronunciation of words. I am also appreciate of the fact that most people can perceive speech easily in spite of variability amongst individuals due to perceptual constancy because it is those people who can understand what I'm saying even if it "sally sold seashells by the seashore" even if most sounds are pronounced wrong.