This study examined the effects of a multimodal vocabulary instruction app on vocabulary learning of first-grade students. The effects of listening to a recorded word explanation was also explored Employing a within-subject design, 69 students practiced 10 novel words on a multimodal vocabulary iPad app. Their performances were compared to another ten words with recorded word explanation and to ten unexplained control words. As a whole group, students learned more word meanings when the additional activity of listening to the recorded word explanation was preceded than when students practiced the new words solely on the vocabulary app. When the students were divided into less-skilled and more-skilled readers, unlike the less-skilled readers who mimicked the whole group’s learning pattern, more-skilled readers learned significantly more word meanings only when students listened to the recorded word meanings and practiced these words on the vocabulary app. This research suggests that regardless of the present reading levels, young readers may benefit the most when a vocabulary app is frontloaded with target word explanations. This study contributes to our understanding of how multimodal app technology can benefit students’ vocabulary learning with varied reading abilities.