List and explain seven social functions of language.

It seems most likely you are asking about Michael Halliday's theories of language. He argues children have seven main functions they use language for. Halliday's theories are often used to critique Noam Chomsky's theories that language is unique and inherent in humans.
The first four are for a child's needs. The last three help a child with their environment.
Instrumental function is when a child uses language to explain a desire.
Regulatory function is when a child uses language to give an order to others.
Interactional function is when a child uses language for relationships.
Personal function is when a child uses language for opinions or feelings
Heuristic function is when a child uses language to ask about surroundings.
Imaginative function is when a child uses language to imagine.
Representational function is when a child uses language to tell things and pass on information.