Literature in the area of measurement of comprehensibility is reviewed as it relates to the utilization of mathematical models for English. A number of mathematical language models are presented and explained, and evidence of their usefulness is given where available. In nonmathematical research, studies concerned with measurement of letter redundancy and other textual constraints are considered as they relate to reading comprehension. Finally, relationships between redundancy and learning are discussed. It is suggested that studies be undertaken to further examine relationships between reading comprehension and mathematical English. References and a glossary are included. (MS)