Differential Effects of Decontextualized, Semi-Contextualized, and Dual-Coding Techniques on Recalling and Retaining of Concrete Vocabulary Items

Lexical knowledge development has always been a seriously challenging task for L2 learners throughout their language learning process, and the necessity of identifying the most efficient L2 vocabulary input encoding for long-term retention is a constant controversy in the field. To address this concern, a quasi-experimental research design was incorporated to explore the effects of single- (Pylyshyn [1978]) and dual-coding (Paivio [1971; 1986]) representation of L2 vocabulary in recall and retention of concrete words in two succeeding and distinct phases. In phase one, four distinct groups of male and female language learners (n=80) received target concrete vocabulary instruction within the single-coding framework via both decontextualized (i.e., word-only L2-L1 flashcards—verbal) and semi-contextualized channels (i.e., picture-supported L2 flashcards—visual). In phase two, three distinct groups of participants (n=60) were provided with decontextualized (verbal), semi-contextualized (visual), and dual-coding (i.e., verbal representations paired with pictures and L1 equivalents) instructions of target concrete words. A comparison of pre-test and post-test scores demonstrated that decontextualized instruction was effective for short-term recall of L2 concrete words in both phases; however, it failed to significantly improve long-term retention of L2 concrete words. Conversely, the semi-contextualized encoding channel significantly well-equipped the L2 learners with two distinct sets of retrieval cues, facilitating both immediate recall and later retention of L2 concrete vocabulary. Meanwhile, the immediate and delayed post-test results of learners who received instruction via the dual-coding channel suggested an additive effect of L2 input representation with L1 equivalents and visual imagery. This combination yielded more remarkable and consistent results in boosting language learners’ short- and long-term recall and retention of concrete L2 words. This implies that exclusively focusing on verbal or visual encoding could hinder L2 learners’ ability in building L2 lexicon in an efficient and progressive manner. The findings suggest the significance of integrating both verbal and visual encoding channels for L2 concrete vocabulary instruction, especially in bilingual and foreign language learning contexts.