When learning a second language, students are taught to read, write, and listen often simultaneously, as it is assumed that it is more effective if both spoken and written versions of the same material are taught together. However, recent research on cognitive load theory and second language learning has shown that a combination of listening to and reading the same material creates a potential for redundancy. Learning can be impeded if the same information appearing in one modality is repeated in the other. The aim of this study was to investigate the consequences of listening and reading on the acquisition of listening skills. Four experiments were conducted. During acquisition, native Arabic-speaking students were required to learn a set of English words and sentences. Learners were either exposed to written work only (single modality), auditory work only (single modality) or written work with an auditory component (dual modality).