The coordination of action in relation to interactions in the medium is called Linguistic Behaviour or Linguistic Interaction. This always takes place when two living systems live together and have structural plasticity in the domain of their recurrent interactions. Structural plasticity is necessary, in that the systems must be able to change their structures when triggered by one another. " The plastic splendour of the nervous system does not lie in its production of 'engrams' or representations of things in the world; rather, it lies in its continuous transformation in line with transformations of the environment as a result of how each interaction affects it." ( Maturana and Varela,1987, p. 170).