This research designs and evaluates a digital format for reading tales in which the text moves at a speed that each child can regulate according to his or her reading ability. The format, called Correpalabras, is a digital application that tries to promote reading at home using the mobile phones of parents. To carry out the empirical evaluation of the format an initial prototype was designed and validated individually with 36 students in second grade of primary education. Then an improved prototype was developed and a pilot test focused on 150 public schools was implemented. The results of both evaluations show that the format produces a high level of interest in children, teachers and parents; and generates a positive impact on attention and reading comprehension. The conclusions suggest that the Correpalabras format helps to consolidate the reading skills of the second and third grade students of primary education and allows the reading to be perceived as a more attractive experience.