The motivation for this empirical study is to make it easier to achieve relatively more fluent dialogue. I sketch a framework for automatically assessing sentence fluency and introduce some statistical techniques that may make corpus characterization and comparisons easier. The technical approach is based on interpreting the language used in a particular situation as a sublanguage of English. Corpus-based statistical models of the English language and its putative sublanguage are constructed and two composite measures of sentence fluency are compared via four non-parametric statistical tests. With one exception, the quantitative results agree with qualitative expectations. Several additional issues are considered and directions for future work are presented.