The word processing depth hypothesis implies a positive association between learners＇ word processing and their lexical learning. In research, learners＇ task-inherent involvement load （i.e., word processing） has not been found to be consistently associated with their lexical learning. Meanwhile, existing studies have not obtained consensus results, either, from directly associating learners＇ actual word processing and their lexical learning. Against this backdrop, this paper reports a study investigating the association between Chinese EFL learners＇ actual word processing and their lexical learning in performing a collaborative oral output task. Interactional and statistical analyses revealed that the participants engaged in four types of word processing; their overall word processing was significantly correlated with both their productive and receptive word acquisition and retention; their different types of word processing were significantly correlated with their productive word learning, but showed variances in correlations with their receptive word learning. The findings were discussed from the perspectives of word processing in collaborative output, word processing and lexical learning, and word processing and different modes of lexical learning.
