Perception of Wordlikeness: Effects of Segment Probability and Length on Subjective Ratings and Processing of Nonword Sound Patterns1

A stochastic phonological grammar based on positional constituent probabilities of words in the mental lexicon was used to generate nonword sound patterns. The subjective wordlikeness of these patterns was evaluated by naïve listeners using a 7-point rating scale. Subjective wordlikeness ratings were lower for nonwords containing low-probability constituents and were also lower for nonwords with more syllables, as predicted by a log product probability metric. However, subjective ratings exhibited a floor effect for very low probability items, demonstrating that there is a limit to the discriminability of low probability patterns. Differences in the processing of these same nonwords which reflected their wordlikeness were also found in a recognition memory task. Nonwords with high-probability constituents yielded better recognition performance, suggesting that participants were able to use their familiarity with frequently occurring lexical patterns to improve recognition for these stimuli. Finally, individual differences in the processing of these nonwords were examined using a test of word familiarity as a measure of lexical knowledge. These differences suggest that participants with greater lexical knowledge (as measured by their familiarity with uncommon real words) were better able to analyze the nonwords into sub-word constituents. Together, these results demonstrate the contribution of the mental lexicon as the foundation of phonological competence, which is reflected in linguistic and metalinguistic tasks involving the processing of novel nonword stimuli.