What distinguishes human natural language from other naturally occurring communicative behaviours and communication systems ? An exclusive focus on syntax tends, paradoxically, to minimize the gap between human natural language and non-linguistic modes of communication. In addition to syntactic and morphological complexity, all natural languages also display symbolic complexity (sometimes referred to as « displacement »), cognitive complexity (in terms of conceptualization subsystems) and pragmatic complexity (linked, in the case of performatives, to symbolic complexity).
In this paper I develop the case that these dimensions of complexity are emergent consequences of the representational function of language, itself definitional, as proposed by Karl Bühler, of the distinction between SIGNALS and SYMBOLS. I argue that Bühler’s signal-symbol distinction is, in terms of psychology of language, a more useful semiotic classification than the better known Peircian triadic classification, inasmuch as icons may be viewed as a species of symbol, and linguistic symbolization is in most cases iconically motivated and always indexically situated.
I propose an account of language evolution based upon the representational development of prelinguistic, intentional communication in contexts of intentional, intersubjective joint reference. The model presented is one in which intentional reference becomes conventionalized and elaborated in processes of semanticization and grammaticalization, about which we know a great deal in the context of historical language change. I discuss the role in language evolution of the niche of infancy, and suggest that the model is compatible with a « late emergence » scenario for evolutionary modern natural languages.
