The relationship of certain cognitive processes with oral and written language is frequently studied, however, there is not enough research that tries to clarify the directionality of these relationships, especially
in students with learning difficulties. The aim of this study is to analyze the effect of an early intervention
program for oral and written language on reasoning in pupils at risk of presenting learning disabilities. The program aims to prioritize and systematize the teaching of oral and written language through
the ordinary school curriculum, through five instructional components: alphabetic principle, awareness
phonology, reading and writing fluency, vocabulary, and text comprehension. A total of 53 girls and boys
at risk of presenting learning difficulties have participated, from four to six years of age. A mixed and
longitudinal research design with repeated measures has been followed, with four phases of evaluation
and three of intervention, two groups of pupils (instructed vs. not instructed) and three study variables
(reasoning, classification and seriation). The evaluation of these variables has been through test of classification and seriation, with adequate validity and reliability. The instructed group has obtained better
scores in reasoning, classification and seriation than the non-instructed group throughoutthe application
of the program. The efficacy of early, systematic and planned intervention of oral and written language
is highlighted as a way to improve certain cognitive abilities in subjects at risk of learning difficulties.
