 This made interesting predictions about adult L2 learning behaviour, for example, that L2 overt morphology should be easier to acquire if the learner has similar overt features in their L1.In one relevant study it was shown that Russian but not Japanese L2 learners of English were, in line with these predictions, reliably sensitive to English plural errors, (Russian has overt plural morphology while Japanese does not).Another important element of these features for GenSLA research is interpretability.