Halliday's functions of language - The most commonly used is instrumental and regulatory which are learnt, along with interactional and personal, at a young age. Representational is used by 6-8 year olds.
Instrumental - Using language to satisfy personal needs, or to accomplish things. Eg: Hungry babies crying to obtain food.
Regulatory - Children use language to control the behaviour of others. Eg: Children may plead with parents to buy a toy for them.
Interactive - Language used to form relationships, express emotions, and strengthen bonds with others. Eg: "I love you Mum"
Personal - Language used to express personal opinions, emotions and identity, as well as to seek information about the world, eg: "Me happy" or "What's that?"
Heuristic - Using language to explore their environment or to seek information (Why don't stars fall out of the sky?)
Representational - Language used to request or relay information between people, exchanging facts or experiences.
Imaginative - Imaginative language used with play in order to create an imaginary world.