Syntax in animal communication: its study in songbirds and other taxa

Many building blocks of human language can be found within the vocal communication systems of other species, most notably songbirds. One of the most prominent of these building blocks is syntax. While studies of syntax are abundant, a lack of consensus on the definition of syntax in non-human animal communication studies has led to much debate. Consistent and deliberate use of terminology is needed to facilitate understanding across disciplines. In addition, new terminology may better describe syntactic structure found in vocal signals that are devoid of semantic associations, such as birdsong. Here, we propose two terms to describe the types of syntax commonly found in birdsong: sequential syntax and dialectical syntax. Sequential syntax can be defined as the rules that govern the patterns of sound without regard to semantic meaning. Dialectic syntax can be defined as sequential syntax that is distinct among different populations or groups with behavioral significance for those groups. Taken together, these two terms can describe the type of syntax seen in ornamental signals, such as birdsong.