Processing instruction in english as a foreign language context: a systematic review

Abstract

This systematic review synthesized 23 empirical studies published from 2015 to 2025 on Processing Instruction (PI) in English as a Foreign Language (EFL) contexts. Following PRISMA-guided searches of Scopus and Web of Science, the review examined grammatical comprehension and production, comparisons with other instructional methods, retention, assessment practices, recent innovations, and methodological limitations. PI and structured input produced the most consistent gains in comprehension and sentence interpretation and generally outperformed traditional instruction on those outcomes. Productive gains were less consistent and were stronger when input-based instruction was followed by structured, unstructured, or collaborative output. Evidence of retention was limited and mixed because relatively few studies used delayed post-tests. Grammaticality judgment, acceptability judgment, and interpretation tasks predominated, creating a receptive-measure bias, while eye-tracking and self-paced reading supplied complementary evidence about online processing. Small, homogeneous samples, regional concentration, short interventions, and limited control conditions constrained generalizability. Overall, PI was best supported as a theoretically grounded, comprehension-first component of grammar instruction that should be complemented by output and communicative practice.