The increased linguistic and cultural diversity of undergraduate classrooms at English language institutions has imposed additional pedagogical and assessment challenges on instructors, many of whom lack the knowledge necessary to design classroom activities and assessments that are fair to all students regardless of students' background and language abilities. The development of an adaptive instrument for instructors who do not specialize in English language learning represents an attempt to adjust instructional practices to meet this need. This paper reports on the development of an instrument that undergraduate instructors can use to plan their courses at universities where English is the language of instruction. The instrument's intended use is illustrated through an example that involves the planning of an interdisciplinary undergraduate course. To build this adaptive tool, a taxonomy that describes the relevant components of assessments that involve oral communication was developed and externally reviewed. The questions used in the instrument were then developed and piloted with a group of university undergraduate instructors; after which, the instrument was further refined. Although piloting revealed an increase in instructor awareness of how language abilities relate to assessment, further research is needed to determine the extent to which this tool affects instructor's classroom or assessment practices.