Learning minimally different words in a third language: L2 proficiency as a crucial predictor of accuracy in an L3 word learning task

This study examines the effect of proficiency in the L2 (English) and L3 (Dutch) on word learning in the L3. Learners were 92 L1 Spanish speakers with differing proficiencies in L2 and L3, and 20 native speakers of Dutch. The learners were divided into basic and advanced English and Dutch proficiency groups according to their scores on general listening comprehension language tests. Participants were trained and subsequently tested on the mapping between pseudo-words and pictures of non-objects. The analysis revealed that, surprisingly, English proficiency but not Dutch proficiency affected word learning in Dutch. We argue that the expansion of the vowel inventory during L2 learning facilitates L3 word learning.