Langauge can of course be used for communication, as can any aspect of what we do: style of dress, gesture, and so on. And it can be and commonly is used for much else. Statistically speaking, for whatever that is worth, the overwhelming use of language is internal – for thought. It takes an enormous act of will to keep from talking to oneself in every waking moment – and asleep as well, often a considerable annoyance. The distinguished neurologist Harry Jerison (1977:55) among others expressed a stronger view, holding that “language did not evolve as a communication system…. the initial evolution of language is more likely to have been…for the construction of a real world,” as a “tool for thought.” Not only in the functional dimension, but also in all other respects – semantic, syntactic, morphological and phonological – the core properties of human language appear to differ sharply from animal communication systems, and to be largely unique in the organic world.