Basil Bernstein began to develop his theory of social structure and power relations during the 1950s and 1960s. Early in the 1960s he met M. A. K. Halliday and Ruqaiya Hasan, who were developing the first formulations of what would become known as systemic functional (SF) linguistic theory. A far-reaching dialogue began. Bernstein recognized the significant role that language plays in the construction of social experience and social inequality. Halliday and Hasan were actively seeking a theory of language that would explain the nature of the social. In different ways, they acknowledged the powerful role of language in the social construction of experience. Their resulting enquiries brought both theories and scholars into dialogue.