What is a proform and how are they used in BSL?

Proforms are sogns that change as you use them. For instance. BSL makes frequent use of proforms: elements that refer to terms previously defined in a given context.

The full sign for "car", is two-handed and is positioned in front of the chest, just like holding a steering wheel. But indicating a car's location, movement, relation to other objects etc. means moving the sign in space/time and in relation to other signs that might be going on simultaneously. So when mentioning a car for the first time youll use the "steering wheel sign". This tells the reader that we're not talking about a car. Then when we continue to mention "the car" we use a proform. For a car, a flat hand-shape with the palm facing down is used. It isnt a differing sign simply a sign that continues to keep the subject (the car) in the conversation.

If during the sign the reader askes "what car was it" They would sign "steering wheel" "what" and "name". The readers face would look quizingly to emphasis "I'm asking".

The response from the first signer would be pointing to the flat hand "car" and then sign "name" and fingers sign the make of the car i.e. finger spell Ford.