This case study describes my introduction to discourse analysis, documents how I broadened my perspective through subsequent readings, and presents a transdisciplinary view of discourse analysis as a way to support credible interpretations of text data. From my dissertation research that explored English Second Language students' learning of science concepts, I had a corpus of rich textual data with possibilities for further insights into science learning in the classroom and was faced with how to analyze these data to yield valid or credible interpretations. This case provides a brief overview of three disciplines--semiotics, functional linguistics, and critical theory--and illustrates how I applied constructs and discourse analysis techniques from these disciplines, leading to the development of a transdisciplinary framework for interpreting discourse or text data. This framework enables the researcher to ask questions about the meaning of the data concerning social and linguistic issues at the macro and micro level of social context. I propose that validity is enhanced when interpretations using this framework at multiple levels show convergence of meanings or themes. A researcher can conduct a transdisciplinary interpretative analysis on any text, disciplinary discourse, or secondary text data, and make a claim that interpretations are valid or credible. [This content is provided in the format of an e-book.]