The teaching and measurement of L2 learners' speech perception has generally focused on high variability phonetic training (HVPT) and phoneme identification tasks. However, it is also necessary to consider how the classroom teacher can assist with perception development. It is argued here that fundamentally,accurate perception requires understanding of the underlying phonological concepts and that once these concepts have been learned they can drive behaviour in both speech production and perception. Because there are many shades of understanding, it is of interest to go beyond a binary assessment of learners' perception. The results presented here are part of a larger project researching the teaching and evaluation of word-stress pronunciation that has been designed for replication. The first rendition found significant quantitative gains were made (Couper, 2022). However, this article discusses the qualitative aspects of the study, attempting to describe and interpret the various shades of conceptual understanding shown by the participants (N=18) and how this changed over time and after instruction. The implications for both researchers and teachers of a new way of testing perception, and the related classroom practices that this testing is designed to reflect, are explored.