This article presents critical issues related to word reading development within Ehri's theoretical context by focusing primarily on the relation of decoding skill (of nonwords) to word reading and the development of unitization. Within this context, issues and considerations related to research, measurement, and reading development are presented from research and field-based perspectives. Analyses examining the relation between a measure of alphabetic principle, "Nonsense Word Fluency" (NWF), and fluency with connected text, "Oral Reading Fluency" (ORF), across first grade demonstrated a linear relation between the measures, which was attenuated for students initially above criterion on the NWF measure. A new scoring approach to the NWF measure is presented to capture initial unitization development and was found to account for unique variance in initial status and growth on ORF and provide instructionally relevant information on the nature of developing alphabetic principle skills. Considerations for future research and school-based applications are provided. (Contains 3 figures, 8 tables, and 2 notes.)