We explored the relationships between L2 utterance fluency and cognitive fluency in monologic and dialogic tasks. The study involved 136 Chinese university-level English learners. Utterance fluency was measured through speed, breakdown, and repair fluency aspects. Cognitive fluency was indicated by L2 lexical and syntactic processing efficiency measures. Stepwise regression models, including metrics of L2-specific cognitive fluency, L2 knowledge, and L1 utterance fluency as predictors, targeted L2 utterance fluency as the dependent variable. We found that L2 cognitive fluency predicted limited variance in utterance fluency, with its influence more evident in monologues. L2 lexical processing efficiency paralleled syntactic processing efficiency’s importance in the monologic task but surpassed it in dialogues. Moreover, L2 processing speed had a more significant impact on utterance fluency than processing stability across both contexts. We suggest that cognitive fluency is not the sole determinant of utterance fluency; L2 knowledge and L1 utterance fluency play non-negligible roles.

We investigate timing and eye-movement behavior during semantic prediction in L1 and L2 speakers of English using the Visual World Paradigm, additionally exploring speech rate. We differentiate first-stage predictions, considered to be automatic and relatively cost-free, from second-stage predictions, which are non-automatic and more cognitively demanding, with differences between L1 and L2 speakers believed to arise in second-stage predictions. We found no differences in the divergence of looks to the target in first- or second-stage predictions across groups. However, speech rate played an important role. Both L1 and L2 speakers showed similar first-stage predictions at slower speech rates, but L1 speakers showed earlier predictions as the speech rate increased. L2 speakers showed reduced and more variable second-stage predictions, suggesting they were impacted during the more demanding second-stage prediction. This may indicate a wait-and-see strategy to help reduce costs associated with second-stage prediction.

This study examined the relationship between intelligibility and comprehensibility in second language speech. Four extended speech samples from 50 speakers spanning a wide range of proficiency were drawn from archived test data. These samples were listened to by 570 English users, who provided comprehensibility ratings and transcriptions to measure intelligibility. The relationship between intelligibility and comprehensibility was strong (r = .81, ⍴ = .88) and nonlinear. A segmented regression model suggested a breakpoint for intelligibility scores (transcription accuracy) at 64%, below which speakers were perceived as uniformly hard to understand and above which increased intelligibility was strongly associated with higher comprehensibility.

We tested masked morphological priming effects with prefixed and suffixed words in L2 speakers of German with L1 Turkish, a language in which prefixes are virtually absent. We found weaker prefixation than suffixation priming, suggesting that cross-linguistic morphological differences between speakers’ L1 and L2 may influence L2 morphological processing. We additionally compared our findings to those of a previous study involving L1 Russian-L2 German speakers and L1 German speakers (Ciaccio & Clahsen (2020). Variability and consistency in first and second language processing: A masked morphological priming study on prefixation and suffixation. Language Learning, 70(1), 103–136). The magnitude of prefixation versus suffixation priming of our group was significantly larger than that reported for the L1 Russian-L2 German group, further corroborating the cross-linguistic hypothesis. However, we found no significant difference between our group and L1 German speakers. Therefore, we additionally consider the hypothesis of a general processing disadvantage for prefixed words as an alternative explanation. We conclude that several factors may contribute to why prefixation, in some studies, proves to be more challenging than suffixation, cross-linguistic influences being possibly just one of them.

Learning to map novel words onto their intended referents is a complex challenge, and one that becomes even harder when acquiring multiple languages. We investigated how label mixing affected learning novel words in one versus two languages. In a cross-situational word learning study, 80 adult participants learned either one-to-one word–object mappings, or two-to-one mappings, reflecting different challenges in learning one or two languages. We manipulated whether mappings co-occurred locally, where repetitions were prevalent, or whether co-occurrences were more distributed throughout exposure. Learners acquired two-to-one mappings better when they did not occur in local co-occurrences, but there was no effect of learning conditions for one-to-one mappings. Whether participants were proficient or not in an additional language did not have an observable effect on the learning. We suggest that local co-occurrences of multiple labels, as in language mixing environments, increase the challenge of learning words, though this effect may be only short-lived.

Embodied cognition theory posits that language comprehension is grounded in sensorimotor experience. For instance, abstract concepts such as perceived power are metaphorically associated with spatial information such as physical size. Here, using a size judgement task, we investigated whether perceived power embodiment differs between languages in Chinese–English bilinguals. Asked to make judgements regarding the physical size of words, participants responded faster and made fewer errors to high-power words (e.g., king) presented in bold and large font than in thin and small font, while no such effect was found for low-power words. Furthermore, this congruency effect was stronger in bilinguals’ L1 (Chinese) than in their L2 (English). Thus, while embodiment of perceived power is detectable in both languages of bilinguals, it appears weaker in the L2. This study highlights cross-linguistic similarities and differences in the embodiment of abstract concepts and contributes to our understanding of conceptual knowledge grounding in bilinguals.

Previous research using cued language switching paradigms has shown a reversed language dominance effect in highly proficient bilinguals, wherein the dominant language is most inhibited. This study investigated cued language switching in highly proficient Spanish–Basque bilinguals (N = 50) using pupillometry, a novel measure of switching cost that tracks cognitive load via pupil size. Response times during cued picture-naming showed faster responses on non-switch than switch trials and faster responses in Basque than in Spanish. These findings suggest balanced proficiency across languages, with Spanish showing overall slowed responses, indicating a reversed dominance effect. Pupil data revealed larger pupil responses for Basque, the less dominant language, suggesting greater cognitive load despite faster naming. This indicates more attentional allocation or activation of the non-dominant language during cued language switching. These results provide insights into the cognitive processes involved in bilingual switching and highlight the value of using pupillometry to explore bilingual language processing.

Whether bilingualism confers non-linguistic cognitive advantages continues to generate both interest and debate in the psychological sciences. In response to mixed reports and methodological critiques, researchers have embraced more rigorous practices when investigating bilingual effects, including those in the domain of cognitive control. Despite considerable advances, one significant issue persists: the assumption that task performance remains stable over time. To address this, the present study investigated the relationship between bilingual language experience and Simon task performance modeled as a continuous function of time. In a sample of Mandarin-English bilingual young adults, we identified distinct patterns of results across both conventional and time-sensitive performance trajectory measures with each supporting a different relationship between language experience and cognitive control. Results suggest that reliance on conventional performance measures may be partially responsible for mixed results, necessitating reevaluation of how bilingual effects on cognitive control manifest and which analysis methods best support their identification.