Natural language is inherently variable and presents a number of challenges for the language learner in identifying which variation to attend to and which can be ignored. In addition to this external variation from the input learners themselves are a source of individual variation that is likely to impact language learning. In recent years researchers have become increasingly interested in understanding the impact of this environmental and individual variation on children’s language development. I will first present a series of experiments that explore the impact of long term exposure to variable input in the form of accented speech from caregivers. These studies illustrate the differing nature of word form representations and word learning ability in two groups of infants, those hearing only the local accent and those hearing more than one. I will then discuss some preliminary data from a longitudinal project tracing the influence of individual variation on vocabulary development and word learning in the early years.