The study of speech sounds is called phonetics. To describe speech sounds it is necessary to decide what an individual sound is and how each sound differs from all others.
This is not as easy as it may seem. A speaker of English 'knows' that there are three sounds in the word cat, the initial sound represented by the letter c, the second by a, and yhe final sound by t, Yet, physically the word is just one continuous sound. You can segment the one sound into parts because you know English. The ability to analyse a word into its individual sound segments does not depend on knowledge of how the sound is spelt. Both not and knot have three sounds, even though the first sound in knot is represented by the two letters kn. Similarly, the printed word psycho has six letters that represent only four sounds ps,y,ch,o.
If you hear someone clearing their throat, you would be unable to segment the sound into a sequence of discrete units because the sounds produced are not sounds in the language. This is because these sounds are not the sounds of any morpheme in a human language; it is not because itis a single continuous sound; you do not produce one sound, then another, then another when you say the word cat. You move your organs of speech continuously to produce a continuous signal.
Although the sounds we produce and hear and comprehend during speech are continuous, everyone troughout history who has attempted to analyse language has recognised that speech utterances can be segmented into individual units. According to an ancient Hindu myth, the god Indra, in response to an appeal by the other gods, attempted for the first time to segment speech into its sperate elements. After has accomplished this feat, according to the myth, the sound could be regarded as language. Indra therefore may be the first phonetician.
Speaker of English can sperate a phrase such as keep out intotwo words because they know the language. We do not, however, pause between words even though we sometimes have that illusion. Children learning a language reveal this problem. A two-year-old child when going down stairs was told by his mother to 'hold on'. He replied, 'I'm holding don', not knowing where the break between words occured. In the course of history, the errors in deciding where a boundary falls between two words can change the form of words. At an earlier stage of English, the word apron was napron; it was mispreceived in the phrase a napron as apron by so many speakers that it lost its initial n.
Some phrases and sentences that are clearly distinct when printed may be sceam, youscream, we all scream for ice cream. Read the following pairs aloud and see why we often misinterpret what we hear :
Grade A
grey day
It's hard to recognise speech
It's hard to wreck a nice beach
The night rate will be cheaper
The nirate will be cheaper
The lack of actual breaks between words and individual sounds often makes s think that speakers of foreign languages run their words together, not realising that we do so also. X-ray motion pictures of someone speaking make this lack of breaks in speech very clear. You can see the tongue, jaw, and lips in continuous sounds. In this way, speech similar to music. A person who has not studied music cannot write the sequence of individual notes combined by a violinist into one changing continuous sound. A trained musician, however, finds it a simple taks. Every human speaker, without special training, can segment a speech signal. Just as we cannot analyse a musical passage without musical knowledge, so we need linguistic knowledge (which requires no special talent or instruction) to segment speech into pieces.
