In this study, 19 college-educated deaf adults with experience using interpreters in educational settings provided insights into how successfully various elements of classroom discourse were preserved through interpretation. The deaf adults, fluent in American Sign Language (ASL) and experienced at using interpreters, watched educational interpreters' renditions of an elementary school art lesson, and answered questions, providing information about the clarity, completeness, and coherence of the message. Next, the deaf adults were asked to compare what they saw in the first interpretation of the lesson to what was conveyed in a second iteration by a highly experienced interpreter familiar with the lesson whose first language is ASL. A control group of 16 hearing adults accessing the lesson directly from the teacher answered the same questions. For the elements of classroom discourse studied--main ideas, project instructions, mental state references, and relevance strategies--results showed a substantial difference between what the hearing participants in the direct presentation condition received and what the deaf adults accessing the message through the educational interpreters received. Qualitative analyses of the differences--between the direct versus interpreted versions and between the deaf participants' responses to the two interpretations--revealed tendencies for, and ramifications of, alterations and omissions in classroom discourse.