The present paper focuses on the evaluation of effectiveness of an educational training aimed to improve the basic cognitive processes implied to read and to write. The main outcome of the study is the reduction in the number of orthographical errors done by the subject enrolled during three kind of examinations. 72 subject attending the third class of a primary school in Lucca (Italy) (mean age 9 years and 4 months) were assigned to the treatment and control class and followed up for two years. The treatment resulted in a improvment of lexicon and in reducing the number of ortographical errors. The treatment proved superior for those initially less skilled (1 mistake saved ever 66 words for children at -1 standard deviation to the mean versus 1 mistake saved ever 18 words for those at +1 standard deviation).