The aim of this study is to introduce a new platform, called "En Plein", for the kinesthetic practice of phonological skills by preschool children and to examine its feasibility in combination with more traditional teaching methods. The rationale is that the manipulation of structural phonological units is important to train the necessary prerequisites for writing and reading and to help the identification of early learning disability precursors. The system includes a large number of phonological activities for children and allows interaction with a playful virtual environment via a cartoon-avatar controlled by a gesture-based natural user interface. "En Plein" relies on the Microsoft Kinect™ motion sensor. In the pilot study, the system has been placed in a classroom of an Italian kindergarten for 5 weeks of training. A test for assessing the phonological skills in Italian language for kindergarten (Valutazione delle Competenze Metafonologiche [CMF]) has been administered before and after training. Children who worked with the platform showed improvements in their phonological awareness (mean increase of CMF scores of 9%), while their peers who received only the traditional education had a mean increase of CMF scores of 1%. Results from this preliminary study show that children who used the system were more confident in manipulating structural phonological units, increased their awareness of words sound structures and generalized these skills by applying them to different tasks. The performance of "En Plein" is particularly encouraging for future large-scale applications in kindergartens and possible tests with children at risk of developing specific learning disabilities.