The impact of multi-word units in early foreign language learning and teaching contexts. A systematic review.

This systematic review reports on research investigating the effectiveness of multi-word unit (MWU) input in instructed foreign language (FL) settings on young learners’ L2 attainment. Recent findings suggest that L2 learners can generalise from MWU input, abstract patterns and employ such schemata productively via slot-filling, indicating that MWUs are key catalysts of learners’ L2 development. At the same time, primary school L2 instruction is on the rise worldwide. Congruously, the importance of MWUs in L2 development is acknowledged in primary school curricula, teacher education and teaching materials: MWUs are considered crucial in the L2 classroom. Therefore, the incentive of this review is to systematically report the state of the art of research regarding the impact of MWU instruction in early L2 teaching contexts. The review covers English, German and French research into typically developing monolingual children aged 5 to 12 learning FLs in instructed teaching settings. Only two of the total results (n=2,233) met the inclusion criteria. Following quality assessment using the Mixed Methods Appraisal Tool and based on a narrative synthesis of available results, we cannot report trustworthy evidence of the effectiveness of teaching MWUs to young L2 learners. We conclude that the extant research lacks robust evidence that MWU input already established in teaching contexts has a measurable effect on specific aspects of students’ L2 attainment, such as productive skills. While we promote MWU’s potential facilitating role in L2 development, we call for more classroom-based intervention research on MWUs in primary school contexts to enable much needed evidence-based recommendations for L2 teaching to support L2 learning outcomes in primary schools.