Fission, fusion and syncretism
A revised model of Tangkic linguistic and cultural history is developed based on a reanalysis of relationships between six Tangkic languages in the southern Gulf of Carpentaria and drawing on recent archaeological and environmental studies. Bayesian phylogenetic analysis of Tangkic basic vocabulary was employed to infer the topology of the Tangkic family tree and define structural branching events. Contrary to previous models suggesting progressive colonisation and fissioning from mainland sources, the data support hypotheses that the modern configuration of Tangkic owes its form to pulses of outward movement from Mornington Island followed by subsequent linguistic divergence in both grammar and lexicon of the varieties. We also speculate that an extreme environmental event (c.800–400 BP) may have flooded low-lying coastal areas resulting in abandonment of some areas, a relatively short co-residence involving cultural and linguistic syncretism between neighbouring groups and then recolonization.