Although research suggests that responsive interactions are imperative for language development, the advent of mobile technology means that parent-child exchanges are often fraught with unpredictable interruptions. Less clear is how these momentary breaks in responsiveness affect word learning. In this within-subjects design, 38 mothers taught their 2-year-olds (M = 27.15 months) 2 novel words, 1 at a time. One teaching period was interrupted by a cell phone call. Children learned the word when the teaching was not interrupted, but not when it was interrupted. Critically, the number of times each target word was spoken did not differ by condition. This finding supports the literature on responsiveness, offering experimental evidence that interruptions in social interactions can affect learning outcomes. (PsycINFO Database Record