Second Look  Asking Good Questions 
Talking about the Greek Cross Meaningful mathematical discourse occurs when tasks are chosen carefully and the teacher steps back and allows students to move to the forefront of their own learning. 
Investigating Mathematical Thinking and Discourse with Ratio Triplets Describes a unique task structure that helps foster classroom discourse and reveals students' mathematical conceptions. The example involves a proportional reasoning task set within a bestbuy context. Three versions of the task are provided which encourage students to consider the meaning of ratios in multiple ways. Several student responses are provided and analyzed. 
Talking Generally or Generally Talking in an Algebra Classroom The ways in which four eighthgrade girls, each with varying levels of algebraic understanding, share ideas, debate, and gradually move toward generalizations inherent in the “Painted Cube” problem. The intent of this article is to examine how students move to progressive formalization and to provide insights into the ways that teachers can foster similar processes among their students. 
Illuminations Lesson: Classic MiddleGrades Problems for the Classroom This
lesson presents two classic problems (Mangoes Problem and Sailors and Coconuts)
that can be represented and solved in several different ways. Middlegrades
students work in groups on the problems to promote communication of
mathematical ideas, and a variety of classroom solution attempts are described.

Communication Standard  PreK through Grade 12 Instructional programs from prekindergarten through grade 12 should enable all students to— organize and consolidate their mathematical thinking through communication; communicate their mathematical thinking coherently and clearly to peers, teachers, and others; analyze and evaluate the mathematical thinking, 