Research has shown that L2 utterances diverge increasingly from target language phonetic norms as the age of L2 learning increases. Other research has suggested that L2 speakers produce longer utterances than native speakers. The aim of this study was to determine whether L2 utterance durations increase as age of learning increases. Fluently produced English sentences spoken by 240 native speakers of both Italian and Korean (selected on the basis of age of arrival [AOA]) were examined. For both L1 groups, the duration of English sentences was positively correlated with AOA. The AOA effect was found to be significant even when confounding variables were partialed out. These results are taken as preliminary support for the proposal that the more established the L1 is at the time of first exposure to the L2, the more it will interfere with L2 production, thus requiring greater processing resources to suppress it.