SATReLO is a tool for the creation of customized applications that support language therapy for children with hearing disabilities. These applications consist of video games that replicate therapeutic activities. Video games can motivate children to embrace therapy positively, increasing the time they dedicate towards this therapy, especially at home. SATReLO allows therapists to customize video games according to the needs of each patient and it keeps a record of his or her progress over time. SATReLO contains a software product line, which makes it possible to derive new video games in real time. The process of testing the system, both in terms of functionality and usability, was thorough and allowed many details of its operation to be fine-tuned. Preliminary tests about the impact of the video games in therapeutic process have been very positive.