Backchannels are a linguistic phenomenon that remains poorly defined. Borrowing of terminology and a reliance on axiomatic definitions has resulted in a diverse nomenclature and an indeterminate inventory of forms. Further, research concentration on backchannels produced in northern hemisphere English has led to the assumption of a common repertoire across all varieties, without supporting empirical investigation. This investigation analysed transcriptions of telephone conversations drawn from the Australian and New Zealand sub-corpora of the International Corpus of English (ICE), and used the ICE corpus mark-up scheme to select potential targets. Chi-square analyses found listeners used single word backchannels more often than more elaborate forms; and Australian listeners produced more backchannels and more single forms. These findings were compared with reported usage by US English listeners, showing that while listeners worldwide draw from a common repertoire of backchannel forms, they differ in the complexity of the structures they use.