How Manual Sign Acquisition Relates to the Development of Spoken Language

Existing evidence is unclear as to how manual sign acquisition relates to the early development of spoken language. The relationship between signed and spoken word productions was examined in a young girl with Down Syndrome during a treatment regimen utilizing simultaneous input. All of her words were recorded over an 8-month period and classified according to the manner and modality of production (i.e., spontaneous/imitated; signed and/or spoken). Certain analyses revealed that most of the words that the subject initially signed were later spontaneously spoken and that most of her signed productions evolved into spontaneous spoken productions. Various patterns were demonstrated with respect to specific word evolutions (e.g., signed to spoken productions), and sign/spoken production tendencies during the first versus last four months of the investigation. It was concluded that use of simultaneous input supports the production of spoken language.