What charaterizes intelligent systems: Issues of language

The human brainware consists of hardware as a neural system and software as a language system. It is said that protolanguage was born two millions years ago. Since then the brain and language have evolved together. It is considered that protolanguage had developed to language with grammar by a hundred thousand years ago. In such a way, language is the most complex system at the highest level among other systems on our earth. Without doubt, human intelligence is based on the functions of language. From this fact it is very natural to characterize an intelligent system by language: capability of handling language or capability of working with language. Discussing some issues of language related to intelligence, we focus on language functions of the brain in this talk. Why can a human speak? It is because the brain contains the system of language in it as a neurocomputational system: not only lexicon and grammar, but also meaning resources, context and mechanisms of understanding and generating texts. The system of language in the brain can be well described in terms of system networks by Systemic Functional Linguistics initiated by Halliday. He points out “four principles to design the language brain”: Stratification, Metafunction, Instantiation and Composition. Stratification is concerned with the hierarchical structure of language as phonology, lexicogrammar, semantics, and context. Metafunction, for example in the semantic stratum, is concerned with ideational, interpersonal and textual meanings. Instantiation is a relation as understanding and generation between meaning resources and texts. Composition is concerned with the logical structure of language.