Robert Worden

Robert Worden

A unified theory of language combines a Bayesian cognitive linguistic model of language processing, with the proposal that language evolved by sexual selection for the display of intelligence. The theory accounts for the major facts of language, including its speed and expressivity, and data on language diversity, pragmatics, syntax and semantics. The computational element of the theory is based on Construction Grammars. These give an account of the syntax and semantics of the worlds languages, using constructions and unification. Two novel elements are added to construction grammars: an account of language pragmatics, and an account of fast, precise language learning. Constructions are represented in the mind as graph like feature structures. People use slow general inference to understand the first few examples they hear of any construction. After that it is learned as a feature structure, and is rapidly applied by unification. All aspects of language (phonology, syntax, semantics, and pragmatics) are seamlessly computed by fast unification; there is no boundary between semantics and pragmatics. This accounts for the major puzzles of pragmatics, and for detailed pragmatic phenomena. Unification is Bayesian maximum likelihood pattern matching. This gives evolutionary continuity between language processing in the human brain, and Bayesian cognition in animal brains. Language is the basis of our mind reading abilities, our cooperation, self esteem and emotions; the foundations of human culture and society.

Robert Worden

A theory of language learning is described, which uses Bayesian induction of feature structures (scripts) and script functions. Each word sense in a language is mentally represented by an m-script, a script function which embodies all the syntax and semantics of the word. M-scripts form a fully-lexicalised unification grammar, which can support adult language. Each word m-script can be learnt robustly from about six learning examples. The theory has been implemented as a computer model, which can bootstrap-learn a language from zero vocabulary. The Bayesian learning mechanism is (1) Capable: to learn arbitrarily complex meanings and syntactic structures; (2) Fast: learning these structures from a few examples each; (3) Robust: learning in the presence of much irrelevant noise, and (4) Self-repairing: able to acquire implicit negative evidence, using it to learn exceptions. Children learning language are clearly all of (1) - (4), whereas connectionist theories fail on (1) and (2), and symbolic theories fail on (3) and (4). The theory is in good agreement with many key facts of language acquisition, including facts which are problematic for other theories. It is compared with over 100 key cross-linguistic findings about acquisition of the lexicon, phrase structure, morphology, complementation and control, auxiliaries, verb argument structures, gaps and movement - in nearly all cases giving unforced agreement without extra assumptions.