Auslan is definitely not a form of English. It has its own distinct lexicon, syntax and grammar just as any other language does. The morphology of Auslan is defined by five parameters: hand shape, orientation, location, movement and expression. Facial expression is as important to Auslan as tone of voice is to spoken language. Without it, meaning would be ambiguous.
English is a second language for most Deaf people living in Australia; Auslan is their first and/or primary language. English usage varies from Deaf person to Deaf person depending on their careers, the need to use English in everyday life and how much they communicate via email and written text.
The grammar and syntax and linguistic structure of Auslan are vastly different to that of English.
When some Deaf people wish to write, they will often use English words that are associated with an Auslan sign and write using the grammatical structure of Auslan. To a non-signing person, this doesn’t always make sense in English and this can alter the perception of a Deaf person’s intelligence. It is also interesting to note that a question in Auslan is shown by a change in facial expression, such as a raised or furrowed eyebrow. The written English skills of a Deaf person can vary depending on how often they use English.