Negative Evidence in Instructed Heritage Language Acquisition: A Preliminary Study of Differential Object Marking

Spanish heritage speakers have been shown to have incomplete knowledge of differential object marking (DOM) (also known as a-personal) in oral and written modes (Montrul 2004a, Montrul and Bowles, in press). In general, Spanish objects that are [+animate] and [+specific] are obligatorily marked with the preposition "a" (Juan conoce a tu hermana "Juan knows your sister"). Other objects are unmarked (Juan compró un perro "Juan bought a dog", Juan escuchó la radio "Juan listened to the radio."). This study investigated the effects of instruction on DOM for heritage language learners. A total of 13 2nd generation Spanish heritage speakers participated in the study, completing a pre-test, instructional treatment, and a post-test. The instructional treatment consisted of an explicit grammatical explanation of the uses of "a" followed by three practice exercises, for which participants received immediate, explicit feedback (including negative evidence). Results of the pre-test confirmed that heritage language learners' recognition and production of DOM is not categorical, as compared with a baseline group of 12 native speakers of Spanish. But post-test results revealed highly significant gains, suggesting that instruction, containing both positive and negative evidence, facilitates classroom heritage language acquisition, as it does second language acquisition (Lightbown 1998, Russell & Spada 2006, White 1989, 1991).