Halliday proposed seven categories of language functions by observing child language development, that is, instrumental, regulatory, represnetational, interactional, personal, heuristic and imaginative.

• 他通过观察儿童语言的发展提出了语言的七种功能,他们是工具功能,控制功能,表达功能,交互功能,自指性功能,教导功能和想象功能。