This paper is a historical and linguistic introduction to some of the missionary translations made by the Reverend Lancelot Threlkeld (1788–1859) into the language (sometimes called 'Awabakal') of the Hunter River–Lake Macquarie region of Australia's east coast. It focuses in particular on Threlkeld's shorter texts, including his 'Selections from the Scriptures', which is the earliest published scripture translation into an Australian language. The paper places Threlkeld and his Indigenous collaborator Biraban in their local historical context, and also in the broader context of missionary linguistics. It considers some unique features of this genre, and focuses on cases where missionary compositions provide the only substantial records of an extinct language (the 'Chibcha phenomenon'). Such cases raise the question of reliability, which we propose can be tested. We use as our example a grammatical feature, the subordinator =pa, to determine the extent to which Threlkeld's construction of subordinate clauses was idiomatic. We conclude that, in spite of a small number of anomalies, which are probably errors, Threlkeld's usage appears to have been remarkably consistent with what we know about the functioning of such clauses in Australian languages in general.