Ambiguity and the origins of syntax

Abstract The paper argues that syntax is motivated by the need to avoid combinatorial search in parsing and semantic ambiguity in interpretation. It reports on a case study for the emergence and sharing of first-order phrase structures in a population of agents playing language games. First-order phrase structures combine words into phrases but do not yet generalise to hierarchical or recursive phrases. To study why human languages exhibit phrase structure, a series of strategies for creating and sharing linguistic conventions are examined, starting from a lexical strategy without syntax and then studying the use of groups, n-grams and patterns. Each time we show in which way a strategy improves on the computational complexity of the previous on.