Copyright © American Speech-Language-Hearing Association From: First-Language Acquisition After Childhood Differs From Second-Language Acquisition:  The Case of American Sign Language J Speech Hear Res. 1993;36(6):1258-1270. doi:10.1044/jshr.3606.1258 Legend: The mean proportion of phonological and semantic-lexical substitutions produced by the subjects during sentence recall as a function of age of ASL acquisition and first versus second language acquisition (for total substitutions produced by each subject summed across all responses). Date of download: 11/12/2017 Copyright © American Speech-Language-Hearing Association