This article presents an elaborated framework for mapping learners' development of nominalizations, one prominent realization of the linguistic resource, grammatical metaphor (Halliday, 1993; Martin, 2008). The framework emerges from a larger, corpus-assisted analysis of the Chinese Longitudinal Learner Corpus (CLLC), 520 Chinese learner texts collected during the students' first four semesters of university (Liardét, 2013b, 2014, 2015). Over the past few decades, SFL research has provided rich descriptions of nominalizations (e.g., Halliday & Matthiessen, 1999; Taverniers, 2006); however, little has been done to empirically describe deployment quality and map learners' development ontogenetically, over time (Baratta, 2010). The proposed framework outlined in this paper seeks to identify how learners develop nominalization proficiency by accounting for intermediate realizations that may otherwise be dismissed as mistakes. These nuanced descriptions are illustrated throughout using excerpts from the CLLC and the paper concludes with pedagogical recommendations for apprenticing learners to advanced nominalization proficiency. •Nominalization is a key resource for achieving the diverse demands of the academy.•This study presents a framework for mapping nominalization proficiency.•Intermediate markers describe the quality of the deployed nominalizations.•Logogenetic descriptors identify the effect of nominalizations on text development.•Detailed descriptions of nominalization intermediacy may inform EAP writing curricula.