Learning L2-L3 cognates and L1-L2-L3 cognates in class: A longitudinal experiment in raising awareness of L2-L3 similarity

We investigated how L3 word knowledge is impacted by similarity to learners’ previous languages (L1 and L2) and awareness of cross-linguistic similarities. Our participants were L1-Polish speakers with L2-English who were beginner learners of L3-Italian (N = 35, M_age = 19.71). Alongside regular classroom activities, we used tailor-made exercises to teach our participants 120 L3-Italian words: 40 L2-L3 cognates, 40 L1-L2-L3 cognates, and 40 noncognates, controlled for a range of item-related variables. We also randomly assigned participants to two conditions: a control group and a cognate-awareness-raising group, where we manipulated participants’ awareness of L2-English-L3-Italian cross-linguistic similarity through interactive online workshops. In the pretest and posttest, we tested learners’ ability to translate an L2-English word to L3-Italian and to use the L3-word in a sentence. Results of mixed-effect logistic regressions showed that the cognates were learned better than noncognates, but there was no difference between L1-L2-L3 and L2-L3 cognates. Importantly, the cognate-awareness-raising training enhanced the learning of L1-L2-L3 cognates, but not of L2-L3 cognates. Our results suggest that any cross-linguistic similarity improves retention, but L3 lexical learning is primarily facilitated by cumulative L1-L2-L3 similarity if the participant is aware of its existence.