Examining spoken features across proficiency levels allows researchers to explore the nature of speaking proficiency as it develops. This line of research has thus far primarily focused on adult second language (L2) learners. Using cross-sectional data based on a large-scale language assessment intended for young L2 learners, in this study, we examined the distinguishing features that categorize the spoken performance of young English language learners (ages 9 to 12) across levels, and especially, between adjacent levels. The study constitutes an initial step in exploring the construct of speaking proficiency of young English language learners as it progresses. The results indicated that 16 spoken features, found to differentiate adult English learners, were associated with young learners' English proficiency. We also found that spoken performance of young L2 English learners was characterized by different features at different levels. Findings of the study provide some preliminary observations regarding linguistic features that show differentiating power at different proficiency levels, offering insights into young learners' English development. The findings can serve as preliminary suggestions for utilizing different rating criteria for constructing rubrics for assessing young learners at different levels of English proficiency.