A LANGUAGE EMERGENCE MODEL PREDICTS WORD ORDER BIAS

The majority of extant languages have one of three basic word orders: SVO, SOV or VSO. Various hypotheses have been put forward to explain aspects of this bias, including the existence of a universal grammar, learnability imposed by non-linguistic-specific cognitive constraints, and the descent of the extant languages from a common ancestral proto-language. Here, we adopt a multi-agent model for language emergence that simulates the coevolution of a lexicon and syntax from a holistic signaling system. The syntax evolves through a process of categorization; local syntactic rules are constructed that assign a relative order (e.g., S before V) to the elements of the two categories to which each rule applies. We demonstrate that local syntax encoding the relative position of S and O are the most stable, allowing the coexistence of the global word order pairs SOV/SVO and VOS/OVS. The structure of the semantic space that the language encodes further constrains the global syntax that is stable.