Second Language Acquisition

The process by which a person learns a language other than their first (native) language. In deaf education and accessibility, second language acquisition theory is particularly relevant because written English is effectively a second language for native signers of American Sign Language, British Sign Language, and other sign languages. Understanding SLA principles — such as the predictable order of grammatical feature acquisition, the role of first-language transfer in creating systematic errors, and the concept of interlanguage — helps inform the design of literacy tools and educational technologies for deaf learners. Recognising English literacy as an SLA challenge rather than a hearing-loss deficit fundamentally changes how technology should support deaf students.