One suitcase, two grammars: what can we conclude about Australian Turkish heritage speakers' divergent processing of evidentiality?

This study investigates the processing of evidentiality using an auditory sentence verification task in heritage speakers of Turkish residing in Sydney, Australia. Evidentiality is a grammatical category that marks the sources of information through which the speaker comes to know information regarding an event. Turkish obligatorily marks two distinct forms of direct and indirect evidentials. We compare the sensitivity to evidentiality-information source mismatches of the speakers of Turkish as a heritage language to Turkish speakers who were late arrivals to Australia. The results show that the heritage language speakers perform less accurately and with longer response times than late arrivals, and both the groups' response accuracy is largely predicted by amount of exposure to Turkish during their development. The data suggest that heritage speakers of Turkish show insensitivity to evidentiality. Moreover, diminishing exposure to Turkish throughout heritage speakers' development appears to be an important trigger for divergent attainment of evidentiality in Turkish heritage grammar.