This qualitative study examined the nature of 5th-grade students' oral and written discourse in relation to their conceptual learning during six science inquiry-based lessons. Qualitative data were collected using small group observations, transcriptions of small group discourse, students' science notebooks, and student interviews. These data were used to create an in-depth illustration of 5th-grade students' discourse and the impact of that discourse on their science conceptual learning. Findings indicated students spoke in three main discourse classifications during small group inquiries and two of these discourses were also present in the science notebook entries. Findings further indicated gender did not impact the nature of students' oral or written discourse regarding their conceptual learning. Implications for classroom practice and suggestions for further research in elementary science education are offered. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]