I draw on longitudinal collaborations with practicing teachers to suggest that a shift in teaching practice can be analogous to learning a new language. Borrowing from research into second-language learning, I offer descriptions of three distinct types of speaker in the mathematics teaching communities which with I work: a few unilingual native speakers (Traditionalists), some fluently bilingual speakers (Reformers), and many speakers of a “mixed language” in which sensibilities are intermingled. While the emergence of mixed-language speakers generally signals significant cultural evolution, it can also be problematical because speakers can appear bilingual well before they understand the nuances of the new language. Consequently, necessary supports are sometimes withdrawn prematurely, before sensibilities are understood deeply enough to transform practice. Using the example of spatial reasoning, and drawing further on the literature of second-language learning, I speak to emerging foci for research, teacher education, professional development, and classroom resources.

Session Type: Plenary Sessions