Metalinguistic explanations and their impact on incidental grammar acquisition: An eye-movement study

Recent research highlights the value of metalinguistic explanations in facilitating second language (L2) grammar acquisition. Nevertheless, a notable research gap persists regarding how these explanations influence incidental grammar acquisition and their impact on overall reading processes and comprehension. Furthermore, whether the potentially positive effects of metalinguistic explanations transfer to the acquisition of subsequent constructions without explicit guidance is an unexplored domain. This study addresses these research gaps by recruiting 42 Korean undergraduate students and assigning them to the metalinguistic or baseline groups. The metalinguistic group read an English text supplemented with bottom-margin metalinguistic explanations, which elucidated the first half of the target grammar (without explanations for the second half), whereas the baseline group read the same text without explanations. This study used eye-tracking technology to register participants’ eye movements during reading, followed by an announced reading comprehension test and an unannounced error correction test. Statistical analyses using linear mixed-effects models (LMMs) and t-tests revealed that metalinguistic explanations significantly enhanced incidental grammar acquisition in L2 learners without compromising overall reading processes and comprehension. However, the benefits of metalinguistic explanations in the metalinguistic group failed to extend to the incidental learning of other unexplained constructions.