The present study investigates the effects of quantity of new second language (L2) vocabulary processing. Previous studies have shown that quantity of processing plays a very important role in learning L2 words, but it has been unclear whether quantity of processing refers to the total amount of time or the number of repetitions of learning.

A study by Zeelenberg, de Jonge, Tabbers, and Pecher (2015) shed light on this issue. In their experiments, they asked English speakers learning Dutch to learn L2-first language (L1) word pairs. In their experiment, the total learning time was controlled across conditions (16 seconds) but the number of repetitions for each word varied. The following five learning conditions were set up: (1) learning the L2-L1 word pairs for 16 × 1 s, (2) for 8 × 2 s, (3) for 4 × 4 s, (4) for 2 × 8 s, or (5) for 1 × 16 s. Recall performance was assessed by the two cued recall tests: L1-to-L2 and L2-to-L1 cued recalls. The participants took one of the two post-tests immediately after the learning in Experiment 1 and one day delayed in Experiment 2. The results of the two experiments demonstrated a nonmonotonic relationship between presentation rate and recall performance, and the performance of 8 × 2 s and 4 × 4 s conditions was better than others.

The present study partially replicated Zeelenberg et al.’s (2015) experiment by comparing the recall performance of 8 × 2 s and 4 × 4 s conditions. As in Zeelenberg et al., the first post-test was administered immediately after the learning. Unlike in Zeelenberg et al., however, the second post-test was administered one week after the learning session, so the present study tried to assess L2 learners’ long-term memory of target L2 words and their L1 translations. The results of the two post-tests demonstrated that the performance of the two conditions was mostly similar either in the L1-to-L2 or L2-to-L1 cued recalls and either in the first or the second post-tests. These results suggest that it is the total amount of time of learning, not the number of repetitions, that is responsible for the effects of quantity of processing in new L2 vocabulary acquisition.