The role of memory in the acquisition of vocabulary and grammar in the first language and in English as a foreign language

Abstract

Previous studies showed that phonological short-term and working memory spans are related to vocabulary and grammar learning in children learning a second language. Typically, short-term storage, as measured by simple span tasks such as non-word repetition, are connected to vocabulary learning. Grammar learning is generally linked to the working memory system. This system is often tested by complex span tasks that require participants to process and store information simultaneously. Yet, few studies have investigated the role of both memory mechanisms in native and foreign vocabulary and grammar learning longitudinally. The current study determines whether phonological short-term and verbal working memory spans contribute differentially to the acquisition of vocabulary and grammar in Dutch as a first language (L1) and in English as a foreign language (EFL). The participants for this study are monolingual Dutch children (N = 138), in grades 4 and 5 (aged 9;0-11;0), learning EFL in the classroom. An L1 and an EFL non-word repetition task were used to measure phonological short-term memory and verbal working memory was measured with a backward digit span task. Receptive vocabulary and production of grammatical knowledge was measured in Dutch and in English, as well as receptive grammar in English. The data indicated that when the same children are longitudinally followed in both L1 and EFL, only past performance is important for L1 vocabulary learning. Phonological short-term memory does not contribute to L1 vocabulary. As expected, working memory span significantly predicts L1 grammar learning. For EFL vocabulary learning, past performance is most important; L1 vocabulary has a smaller but independent role and in line with previous research, phonological short-term memory also has an independent role. For both receptive and productive EFL grammar learning, contrary to expectations, working memory span did not play a role. In contrast, EFL phonological short-term memory had a small but independent role for receptive grammar learning. EFL vocabulary had a similar role for receptive and productive grammar, which was stronger than EFL phonological short-term memory for receptive grammar. However, past performance had the largest role for both types of grammar learning. In sum, when looking at the initial stages of EFL in a formal setting, we only found a role for working memory span in L1 grammar but not in EFL. Phonological short-term memory only had a role in EFL vocabulary and receptive grammar learning, and was language specific. In all, the current data show that in addition to phonological short-term memory, past performance on vocabulary and grammar contributed significantly to vocabulary and grammar learning and that the role of vocabulary and phonological short-term memory and working memory span in grammar learning is language specific.