Current theories of speaking suggest that the structure of the lexicon is flexible and changes with exposure. We tested this claim in two experiments that investigated whether the word frequency effect was moderated by item repetition within and across experimental sessions. Participants named high frequency (HF) and low frequency (LF) pictures (Experiment 1) and words (Experiment 2) six times. In both experiments, participants were faster to name HF than LF pictures or words, but this effect was eliminated with repetition. Importantly, this word frequency effect was still absent when participants returned up to 2 weeks later and named old HF and LF pictures, whose names they had produced before, together with new HF and LF pictures, whose names they had not produced. These findings suggest that producing a word multiple times in short succession alters its long-term accessibility, making it easier to produce later.