PLL4, hosted by Cape Breton University, Sydney, Nova Scotia CANADA is based on the theme “Currents and Waves.” We welcome presentations on a wide range of topics relating to the many long-running currents of thought and new waves of research about psychology of language learning with emphasis on the development of second or foreign languages. This is an in-person event with an online component. We welcome everyone with an interest in the psychology of language learning and use.