From an examination of the emergence of Batua, dialect classification, the relationship of sixteenth century Basque to Batua, two sets of sixteenth century sources, the thesis contends that, over the last half-millennium, Basque has changed to a greater extent than generally acknowledged. Semantic, aspectual, syntactic, phonological and morphological change is illustrated, showing how different sources reflect different stages of key transitions. Investigation of the morphosyntax of sixteenth century person-related markers contrasts patterns of distribution, positioning, pleonasm and omission with those of the modern language. Indexing between pre- and post-root features suggests a history of serial verbs, or possibly root suppletion; in particular the shift from sixteenth century predominantly pre-root (where they exist) to the modern overwhelmingly post-root positioning of dative flags lends weight to the contention that Basque might have transitioned from a language with previously greater pre-inflective typology than the overwhelmingly post-inflective language of today. Sixteenth century intermediate forms permit insights into an earlier history of reanalysis and repurposing and suggest foci for future research
