Recent studies have shown that giving an explanation improves the speaker’s comprehension when they use their mother tongue. However, this effect is insignificant when they use a second language (L2). This study explores an effective support method that aims to help L2 speakers to get a deeper understanding of the subject after explaining it to a peer. Twenty-nine Chinese international university students participated by reading a statistical dispersion text written in Japanese. They were then asked to explain the text in Japanese to their peer. The students were put into four groups for comparison: i.e., (1) the control group received no prompt before reading (n=10); (2) the content support group were given prompts before reading that aimed to provide an explanation of the contents (n=7); (3) the structural support group were given prompts before reading that aimed to provide a structured explanation (n=6); and (4) the content and structural support group were given prompts about content and structure (n=6). The results showed that methods (3) and (4) were more effective, while method (2) had a limited effect on improving understanding. A protocol analysis of the explanations showed that better explanations could be made under supportive conditions. These results demonstrate the necessity of providing support for L2 speakers to get a deeper understanding after explaining a concept to a peer.