Second language (L2) fluency research has suggested that a range of linguistic knowledge and processing speed serve as cognitive fluency (CF) underlying L2 utterance fluency (UF). Building on prior CF-UF link studies, this study explored L2 collocational processing speed and accuracy as underlying CF measures. This study also explored the phrasal frequency effect on the relationship between collocational processing speed and UF to test whether the processing speed of higher-frequency collocations is more strongly related to UF. A total of 108 Japanese university students completed a phrasal acceptability judgment task with adjective–noun collocations pooled from the Academic Collocation List. Speech was elicited in an argumentative speech task, and UF measures were computed based on speed, breakdown, and repair fluency. The results revealed that the collocational processing speed was weakly tied to articulation rate and mid-clause and end-clause silent pause ratio (rho = |.271–.322|), while the collocational processing accuracy was weakly to moderately tied to most UF measures except filled pause ratio (rho = |.281–.368|). The collocation frequency moderated the relationship between the processing speed and UF, suggesting that high-frequency collocations served as a proxy for automaticity in speech production. Implications for CF-UF link research are discussed.

Given that utterance fluency in a second language (L2) is associated with not only L2 cognitive fluency but also utterance fluency in the first language (L1), the study examined to what extent different measures of L2 utterance fluency can be explained by L2-specific cognitive fluency and/or the corresponding L1 utterance fluency measures. Utterance fluency measures on speed, breakdown, and repair phenomena and cognitive fluency measures including speed of lexical retrieval, syntactic encoding, and articulation were collected in the L1 and the L2 from 44 Chinese learners of English. The results show that most L2 utterance fluency measures are accounted for by the combination of L2-specific cognitive fluency measures and the equivalent L1 utterance fluency measure, whereas the number of mid-clause silent pauses and corrections, and mean syllable duration are largely explained by L2-specific cognitive measures, suggesting that they reflect L2-specific knowledge and cognitive skills. In contrast, mean silent pause duration and the number of filled pauses are mainly explained by the corresponding L1 utterance fluency measures.

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.