Psycholinguistics -- the field of science that examines the mental processes and knowledge structures involved in the acquisition, comprehension, and production of language -- had a strong monolingual orientation during the first four decades following its emergence around 1950. The awareness that a large part of mankind speaks more than one language -- that this may impact both on the way each individual language is used and on the thought processes of bilinguals and multilinguals, and that, consequently, our theories on human linguistic ability and its role in non-linguistic cognition are...