Inspired by the Developmental Individual-difference Relationship-based (DIR) model of first language acquisition and Emotion-Based Language Instruction (EBLI) in bilingual education, the current study explores the function of emotioncy as an effective benchmark for vocabulary teaching. In particular, it attempts to empirically extend the earlier work on emotioncy, investigate learners' vocabulary development, and draw a link between learners' emotioncy and their diverse socio-economic backgrounds. In order to do this, 45 English language learners were selected from schools located within various regions of Mashhad, Iran with high, mid and low socio-economic status. Thereafter, a list of 21 vocabulary items was taught to them during 4 successive sessions. At each session, 7 words were presented to the learners and finally their retention was examined by means of immediate and delayed tests. To analyse the data, MANOVA was run to detect the likely influence of emotioncy on learners' ability of vocabulary learning and retention. Subsequently, ANOVA was employed to determine the probable discrepancies among the three groups of learners. Lastly, Pearson Product Moment Correlation was utilised to investigate possible correlations between learners' tests and their level of emotioncy, English score and overall GPA. The findings indicated that learners from the high socio-economic class outperformed their counterparts from the mid or low social class, concluding that learners' economic/social/cultural capital significantly determines their degree of emotioncy. Furthermore, the learners' emotional competencies surpassed their cognitive abilities in accounting for their general vocabulary learning success. Finally, some suggestions and implications were provided within the realms of vocabulary learning and language education.