Many studies have suggested that personal practical knowledge is essential for professional development. Recently, there has been growing recognition of the importance of teacher educators’ personal practical knowledge of ‘language’ for student learning development. However, the need for teacher educators to first understand their own language-oriented development in content-based classroom interaction has not received as much emphasis. The current intervention study investigates how eleven experienced teacher educators understand their language-oriented development through the control of task difficulty, small-group instruction and directed response questioning. Data were examined by conducting content and constant comparison analyses. The results showed that the intervention affected the educators’ language-oriented development, which in turn affected their awareness and decisions made to improve their methods of initiation and response during classroom interaction. The results call for more concrete ways to expend teacher educators’ practical knowledge of language to further develop and enhance their language-oriented teaching performance in content-based classroom interaction.