The acquisition of split-ergativity in Kurmanji Kurdish
Previous research about the acquisition of the case-marking systems of ergative languages suggests that children acquire ergative and accusative languages equally easily (Van Valin 1992), depending on the degree to which the case morphology is consistently ergative or accusative and the degree to which adults use the morphology (Pye 1990). However, split-ergative languages incorporate both accusative and ergative systems, some in the midst of a shift away from ergativity, thus providing variable and inconsistent input for children. Yet previous research suggests that children can acquire variable linguistic forms at early stages, reflecting frequencies in which the forms occur in caregiver input (Henry 1998, 2002, Miller 2006, 2007, Westergaard 2009). This study examines the acquisition of split-ergativity in Kurmanji Kurdish, where the direct case is used with both present-tense agents and past-tense patients and the oblique case is used with past-tense agents and present-tense patients. However, recent research suggests the weakening of ergativity in Kurmanji (Dorleijn 1996), resulting in variable use of case-marking. This study examines the acquisition of split-ergativity in Kurmanji when considering the split systems and inconsistent adult input. Data from children (n=12) and caretakers (n=24) include spontaneous speech samples and results from a modified Agent-Patient test (Slobin 1985). Four children from three age groups, 1;6, 2;6, and 3;6, were recorded interacting with caretakers every three months for one hour over a 12-month period. Statistical analyses were conducted focusing on adult patterns (input for children) and children’s production at different ages. Results suggest that Kurmanji may be shifting away from a split-ergative system, with the past tense extending to a double oblique pattern and nouns gradually losing oblique case-marking altogether, resulting in variable case-marking. Data show that children first use ergative case as early as 2;0 and show evidence of repeated use of split-ergative case-marking by 2;6. Even at these early ages, children use similar variability and frequency in case-marking as their caretakers, closer to usage of younger adults versus older adults. Thus children seem to use ergative case-marking early, and when faced with inconsistent input, they ultimately conform to the patterns modeled by the adult community.