Australian vernacular refers to the unique language and expressions used by Australians. It includes slang, idioms, and colloquialisms that reflect the country's culture and lifestyle. For example, terms like "arvo" for afternoon and "bikkie" for biscuit are commonly used in everyday conversation. This vernacular often incorporates influences from Aboriginal languages, British English, and immigrant languages, creating a distinct way of speaking. Australians are known for their informal and friendly communication style, which is evident in phrases like "no worries" and "mate," emphasizing a laid-back attitude and camaraderie.