ABSTRACT
This chapter examines sign language development under such circumstances, starting with studies of children and young people, followed by studies with adults who were tested decades after they began signing. It discusses the adults who are learning a sign language as a second language when their first language was spoken. The chapter provides a few findings that have emerged and mention areas for future studies and reviews some research on the learning of the written version of a spoken language by deaf signers. There are many studies that compare results on American Sign Language (ASL) tests for native signers (with input from birth) versus non-native signers (whose input begins at various ages). The parallels between deaf readers and hearing bilinguals have also been demonstrated. Researchers investigating bilingual processing have found evidence that both languages are active in a bilingual even in contexts that only require one language.
