Makaton was devised in the 1970s by speech and language therapist Margaret Walker and colleagues Katharine Johnston and Tony Cornforth. Throughout the 70s and 80s, Walker worked with the deaf and people with severe communication difficulties to develop a Makaton vocabulary, initially comprised of sign language only but later including symbols. Makaton now has a core vocabulary of 450 concepts which are taught in eight stages, the earlier of these including basic needs like eating and sleeping, the later more complex or abstract concepts like time or emotions.