A discussion of the connections between mathematics, language, and second language acquisition focuses on four major areas: (1) the nature of mathematical performance, (2) the language of mathematics, (3) problems that mathematics poses for limited-English-proficient (LEP) children learning English as a second language, and (4) mathematics as a facilitator of second language development. It is argued that the effectiveness of mathematics instruction for second language development is more complex than making the language input comprehensible, lowering the affective filter, and providing for interactive situations with peers and the teacher. Successful mathematics processing rests at least in part on the ability to use the very precise language of mathematics in mathematical reasoning. The context-reduced language of mathematics, extensive use of logical connectors, specialized vocabulary and syntactic structures, and appropriate discourse rules all present complex problems to (LEP) children engaged in mathematics discourse. These problems seem to be linked to some underlying deep structures in mathematical thinking, a process that is analogous to cognitive/academic language proficiency. If these relationships are understood and addressed in the mathematics classroom, language need not be a barrier to processing mathematics in a second language. (MSE)