EN
This paper aims to study the effect of the immersion in a second language on the processing of the mother tongue, from the viewpoint of dual-route theories. Therefore, a lexical decision experiment was run where Spaniards residing in the United States had to respond to four types of critical stimuli: Spanish complex words (aceptación), non-allowable morphological pseudowords (acepteza), allowable pseudowords based on the corresponding English word (aceptancia, from acceptance) and allowable pseudowords based on the substitution of the normative suffix by an alternative one (aceptamiento). The results show a significant difference in the way native speakers process complex words depending on the language of context. When they were immersed in an English context, a processing cost could be observed, as well as a correlation between the frequency of the English cognate equivalent (acceptance), more frequent contextually. On the other hand, the best processing predictor for the Spaniards in Spain was the frequency of the actual Spanish word (aceptación). These results give support to a contextually driven processing of our mother tongue.