In order to verify our hypothesis that a certain trigger is necessary to facilitate L2 learners' communication strategy transfer to speak English, this study examined the effects of implicit and explicit cues on English utterances by Japanese speakers. Ten Japanese university students viewed a video of city-walking in New York or in Tokyo, and uttered as much as they could about anything they saw or felt in English. Video was projected on a hemisphere screen with stereo sound, so that participants had a virtual-realistic experience. At the beginning of the second phase of the experiment, participants were given an additional instruction to do the task as if they were guiding the street to video-viewers. The results showed that participants made more subjective expressions in the second phase of the experiment than the first, indicating the effect of the additional instruction as an explicit cue. Moreover, they made more objective descriptions when viewing the New York video than the Tokyo video, indicating the effect of a simulated English environment as an implicit cue. These results, which are consistent with our previous findings, were discussed in light of a theoretical contribution to the communication strategy and the practical implication of English education.