When Roger Brown selected Adam, Eve and Sarah to be the first three participants in the modern study of child language, one of the criteria was the intelligibility of their speech (Brown, 1973). According to the prevailing view at the time, accuracy of pronunciation was a peripheral phenomenon that had nothing to do with the development of language "qua" language. So why not study children who were easy to transcribe? One reason why not, according to Stoel-Gammon (SG; this issue), is that the difficulty of accurately producing sounds influences the words children acquire and the rate at which they acquire them. (It's true that Roger Brown's focus was on the child's acquisition of morphosyntax, but articulation was assumed to be peripheral to everything back then.) This interaction between the articulatory skill of children and phonological properties of words is just one of the mutual influences between phonology and the lexicon SG describes. In her target article, SG brings together data from a wide range of investigations to build an account of how phonology and the lexicon interact in development.