Word frequency effects in oral reading are not merely age-of-acquisition effects in disguise

Four experiments examined the effects of the rated age of acquisition (AoA) and word frequency on oral reading latencies and word pronunciation durations. In Experiment 1, both AoA and frequency had independent (and noninteracting) effects on naming latencies. Experiment 2 found no effect of either AoA, or frequency on delayed naming, indicating that prepared articulation time was not a factor contributing to the naming latencies observed in Experiment 1. Experiment 3 reported 2 replications of the study by C. M. Morrison and A. W. Ellis (1995). Both replications found reliable effects of frequency and AoA, whereas Morrison and Ellis found an effect of AoA but no effect of frequency. Experiment 4 found a strong AoA effect on pronunciation durations, with a smaller and less reliable effect of frequency. It was concluded that frequency affects the visual recognition of words and that AoA affects the production of lexical phonology.