Techniques for integrating English-as-a-Second-Language (ESL) instruction and mathematics instruction, particularly the language of mathematics, are discussed. Focus here is on mathematics instruction for limited-English-speaking students in the mainstream classroom. First, examples of the academic language of mathematics that students must develop are outlined. Some instructional techniques that incorporate students' own language and background in the construction of mathematics concepts and formal mathematics register are then offered. These include: techniques to make mathematics lessons more comprehensible and ways to promote interaction and provide a classroom environment conducive to language and literacy acquisition; methods for maintaining high expectations for language minority students and helping them develop higher-order cognitive and metacognitive skills and strategies; and assessment of language development alongside conceptual knowledge. A concluding discussion looks at the roles of content-area and ESL teachers in the overall education of language minority students and the need for collaborative efforts to ensure effective language and knowledge development throughout the school day. Contains a 13-item list of sources of information and materials, and a 36-item bibliography. (MSE)