Syntax, Phylogenetics, and Language Contact

Language histories are often considered in terms of genetic relationships, which are often represented using phylogenetic trees. Traditionally, these relationships have been uncovered through the application of the comparative method to sets of cognate lexical items, with only a minor focus on morphological evidence and virtually no consideration given to syntax. More recently, computational methods have been employed for the inference of phylogenies; however, most work has focused on vocabulary cognacy. The Parametric Comparison Method (PCM; described by Longobardi & Guardiano, 2017), by contrast, uses a set of syntactic parameters which account for cross-linguistic variations to generate syntax-based phylogenies. To explore whether evidence of language contact — a secondary concern in previous PCM work — can be found in syntactic phylogenies generated using the PCM, I created a novel parametric database through the combination of Ceolin et al.’s (2021) nominal database and Baker and Roberts’ (In prep.) clausal database. I examined phylogenies generated from this database for their adherence to traditional phylogenies and for evidence of language contact leading to syntactic transfer in the histories of Celtic, Germanic, and Romance. My findings suggest that parametric syntactic phylogenies can provide evidence of language contact, and this is exemplified by a case study involving Afrikaans and English. However, contact effects are subtle and require careful examination of phylogenies and individual parameter settings. I argue that models of linguistic history, including those based on syntax, should account for language, as language contact is an essential component of the story of any speech community.