The early the better? Or, the more the merrier? the relative effects of onset age and exposure hours on EFL learners' implicit and explicit grammatical attainment

Drawing on methodological insights from psycholinguistic research protocols, the present study employed a structural equation modelling approach to examine whether explicit and implicit grammatical knowledge of English language learners would be influenced by their onset age of language learning and hours of exposure to language instruction; and if so, in what way? The present study further examined how the hypothesized causal effects might be mediated by explicit and implicit grammatical knowledge. The results showed that while early onset appeared to exert a facilitative effect on the participants' implicit grammatical attainment, the role of exposure to instructed input was more relevant to their explicit grammatical attainment. Importantly, early onset facilitated the participants' implicit grammatical attainment more than their explicit grammatical attainment, most likely because early learners' analytical learning mechanism was still immature. Notably, while superior implicit grammatical attainment was conducive to the participants' explicit grammatical attainment, their better explicit grammatical attainment did not necessarily facilitate their implicit attainment. The insights of this study shed light on the necessity of implementing early foreign language education when the curriculum goal concerns developing learners' intuition regarding the FL, and provides empirical evidence of the need to adjust current instructional hours and foci in school.