In this paper, the author presents a detailed discussion of the development and applications in language learning and language processing of his model of working memory with particular focus on the role of the so-called ‘phonological loop’. The phonological loop maintains acoustic or speech-based information for a short time, thus making it available for comprehension, production and acquisition. The discussion may have implications for simultaneous interpreting since the types of language processing involved put specifically heavy demands on the interpreter’s memory and attention.