An important characteristic of human language is 'arbitrariness'. This means that there is no direct connection' between the sound or form of any word and the object which it represents. As we know that languages uses only a small number of distinct sounds and these are not generally allowed to directly convey any meaning. These sounds are used to represent morphemes and it is these latter entities which are allowed to function as meaningful elements in language. There is apparently no natural relationship between the various sounds that are used by these languages to these sequences and the meaning that is denoted by them. We see that the relationship between sound and meaning is completely arbitrary. However, it is also possible that the occurrence of certain onomatopoeic words such as wiper will, hiss, murmurs, buzz etc. constitute a remnants of that original situation.
It might be even claimed that the occurrence of an indirect connection between sounds and meanings must have allowed the sounds and higher linguistic elements to under go various kinds of changes rather independently of one another; hundreds of such changed must have taken place during the long history of languages. It must be clear that the existence of arbitrariness does not imply that a speaker is free to use whatever sounds or sequence of sounds that comes to his mind to represent a given meaning.
It might be even claimed that the occurrence of an indirect connection between sounds and meanings must have allowed the sounds and higher linguistic elements to under go various kinds of changes rather independently of one another; hundreds of such changed must have taken place during the long history of languages. It must be clear that the existence of arbitrariness does not imply that a speaker is free to use whatever sounds or sequence of sounds that comes to his mind to represent a given meaning.