The present study investigated the age of acquisition (AoA) effect in processing second language (L2) words and how it is related to the AoA of the corresponding first language (L1) words. We adopted a lexical decision task in three experiments. The filler words were orthographically illegal in Experiment 1 to elicit more word form processing, while Experiment 2 used legal fillers to shift the bias toward semantic processing. In Experiment 3, we used a larger amount of stimuli containing more longer words with legal fillers. Our results showed that L2 AoA has a weak effect at the orthographical processing level and a stable effect at the semantic processing level. The L1 AoA modulates the L2 AoA effect at the semantic processing level, which is more likely to appear in long words. These results suggest that it is important to take bilingual representation and activation into consideration to explain the L2 AoA effect.

Speech disfluency in first language (L1) and second language (L2) is not only quantitatively different (e.g., number and length of pauses) but also qualitatively different (e.g., distribution of pauses); however, how pause distributions in L1 and L2 affect judgments of perceived fluency is unclear. The study examined the relationship between pause phenomena and perceived fluency using two experiments. Experiment 1 investigated the relative contributions of frequency, length, and distribution of silent pauses to perceived fluency of L2 speech. Experiment 2 tested causal effects of pause location on perceived fluency of L1 and L2 speech using phonetic manipulations. Findings suggest a significant role of pause location in perceived fluency. In Experiment 1, silent pause rate within a clause demonstrated the strongest correlation with L2 fluency ratings, and in Experiment 2, perceived fluency of L1 and L2 speech was influenced by pause location. The findings suggest that listeners seem to be sensitive to pause location and to understand that pauses within clauses tend to reflect reduced cognitive fluency.