A review of sign language acquisition studies as the basis for informed decisions for sign language test adaptation The case of the German Sign Language Receptive Skills Test

Developing or adapting tests of sign language development requires knowledge about the emergence and mastery of the linguistic structures that should be represented in a test. As the structures and acquisition of many sign languages are rather under-documented, developing or adapting a test for a specific sign language poses a great challenge for test developers, especially with respect to the test's reliability and validity. For a research project which adapted the British Sign Language Receptive Skills Test (Herman, Holmes & Woll 1999) to German Sign Language (DGS: Deutsche Gebardensprache; Haug 2011a), there existed only one study on the acquisition of DGS, which focused on verb agreement (Hanel 2003, 2005). Hence in lieu of DGS-studies, studies of other sign languages were reviewed that focused on the acquisition of linguistic structures represented in the original BSL test selected for the targeted age group (> 3 years old): agreement verbs, AB verb constructions, classifier constructions (spatial verbs with whole entity classifiers, size and shape specifiers, and handling classifiers), negation, and number and distribution. This paper presents this review of the most recent acquisition studies of the linguistic structures mentioned above and represented in the BSL test. The main focus is on studies that covered the age range of 4 to 8 year-olds, the age group of the adapted DGS test. The argument will be made that - considering the current state of research for many sign languages - these acquisition studies from a variety of sign languages can serve as the basis for making informed decisions for test development and adaptation (for example, deciding which items should be represented in a sign language test), but only together with cross-linguistic and language specific studies.