Dialect separation and cross-dialectal influence: a study on the grammatical gender of Oromo

The extent to which the grammar of one dialect influences the grammar of another and the mechanisms that bidialectal speakers employ to distinguish a target grammar from non-target grammar have not been adequately investigated. In this study, we elucidate these issues by investigating the grammatical gender of Oromo, a Cushitic language that is spoken in Ethiopia. The results from two successive offline experiments indicate that Oromo bidialectal speakers can differentiate between the grammar of their native dialect and that of a non-native dialect in both spoken and written modes. This finding implies the existence of a dual-system representation of grammar. Moreover, there is a significant amount of dialect mixing that varies across various developmental stages and modalities. The bidialectal speakers’ ability to differentiate between the grammar of their native dialect and that of a non-native dialect is constrained by the magnitude of their exposure to the non-native dialect, modalities, and a specific property of grammatical forms. Here, we propose an interactive dialect separation model that accounts for diverse dialect contexts.