Processing Instruction (PI) has gained significant attention as an input-based pedagogical approach, yet its specific contribution to speaking development among non-English major students remains insufficiently explored. This bibliometric and empirical synthesis examines research trends, thematic focuses, and pedagogical implications of PI for enhancing speaking proficiency. Using Scopus data from 2000 to 2025, 542 publications were analyzed with VOSviewer© to identify patterns in scholarly output, keyword co-occurrence, and conceptual evolution. Findings reveal increasing interest in PI over the past decade, with emerging emphasis on communicative competence, fluency, affective factors, and multimodal instructional contexts. Empirical evidence indicates that PI strengthens form-meaning connections, reduces speaking anxiety, and supports real-time pragmatic performance, particularly when embedded within learner-centered, pre-speaking instructional stages. Despite promising outcomes, gaps persist regarding direct speaking assessments, longitudinal effects, and non-English major contexts. The review highlights PI’s potential to inform innovative curricula and calls for targeted research integrating PI with communicative teaching models.