Morford & Carlson (2011)
Morford, J. P. & Carlson, M. L. (2011). Sign perception and recognition in non-native signers of ASL, Language Learning & Development, 7 (2), 149 – 168. ____________________________________________________________________________________________
Past research has established that delayed first language exposure is associated with comprehension difficulties in nonnative signers of American Sign Language (ASL) relative to native signers. The goal of the current study was to investigate potential explanations of this disparity: Do nonnative signers have difficulty with all aspects of comprehension, or are their comprehension difficulties restricted to some aspects of processing? We compared the performance of deaf nonnative, hearing L2, and deaf native signers on a handshape and location monitoring and a sign recognition task. The results indicate that deaf nonnative signers are as rapid and accurate on the monitoring task as native signers, with differences in the pattern of relative performance across handshape and location parameters. By contrast, nonnative signers differ significantly from native signers during sign recognition. Hearing L2 signers, who performed almost as well as the two groups of deaf signers on the monitoring task, resembled the deaf native signers more than the deaf nonnative signers on the sign recognition task. The combined results indicate that delayed exposure to a signed language leads to an overreliance on handshape during sign recognition.