Teacher principles encompass a teacher's stated assumptions, beliefs, and conceptions about acquiring and teaching a second language (L2). Due to the complex and diversified nature of how principles take form, an individual teacher's principles will influence their judgements, perceptions and instructional decisions, thus affecting the outcome of classroom practices. Exploring teacher principles and their impact on classroom practices and vice versa is an invaluable and necessary component to research in L2 teaching and learning since it plays an influential role in instructional outcomes. This paper explores the nature of the principles/practice relationship through an investigative case study with an ESL teacher of L2 speaking. Additionally, the results of research on principles and practices related to L2 teaching when conducted by academics rarely gets back to teachers in the front lines. Thus the researchers shared their findings with the teacher who as a result of reflecting on the analysis came up with a set of principles she says guides her teaching of L2 speaking.