The ultimate advantage of starting foreign language instruction at a very young age has been hard to demonstrate empirically (Jaekel 2017). The dominant hypothesis is that instructed foreign language settings do not provide young learners with the amount of input necessary for their cognitive advantages to express themselves (Singleton 2003). One avenue for research is to maximize the quality of the input learners receive in class and the efficiency with which they are led to process it (Van Patten 2002). In order to do this with 6-year-old schoolchildren learning English in France, a serious game was designed, to be played on tablets. The game targeted 40 words, and combined systematic activities promoting form-meaning pairings with contextualization through the use of a storyline in which the activities were embedded. The goal was to help learners recognize the same word in different contexts and in different voices, producing more robust lexical representations. A classical pretest- treatment- posttest design was used, with 690 participants (49 intact classes), half of whom were acting as the control group. The treatment lasted 10 weeks (10 hours of playtime). Preliminary analyses of the results show that the experimental groups outperformed the control groups by a significant margin in the delayed posttest in English (p<.001). The effect was especially noticeable for easy words and word combinations.