Listeners flexibly adapt utterance interpretation based on speaker characteristics, but less is known about how this works in multiparty conversations, particularly for pragmatic inferences like Mutual Exclusivity (MEI) – the tendency to map novel terms onto unnamed referents. MEI may reflect a flexible, speaker-sensitive process or a rigid default. This study tested whether listeners modulate MEI based on speaker-specific referential consistency in multiparty conversations. Two eye-tracking experiments were conducted (Exp 1: N = 32, English; Exp 2: N = 44, Spanish), where participants followed instructions from two speakers. In experimental conditions, one speaker was consistent (reused labels), while the other was inconsistent (sometimes relabeled objects). Control conditions featured two consistent speakers. Results showed robust and early MEI across conditions. No speaker-specific adaptation occurred, but Experiment 1 showed context-general adaptation: exposure to an inconsistent speaker within a conversation reduced MEI overall. Findings suggest that in high-demand communicative contexts, MEI operates as a strong default heuristic, largely resistant to speaker-level inconsistency. Evidence for sensitivity to broader contextual reliability was observed in Experiment 1 but did not replicate in Experiment 2, leaving open whether MEI exhibits limited contextual flexibility or whether the initial finding reflected design-specific factors.

Monolingual children tend to assume that a word labels only one object, and this mutual exclusivity supports referent selection and retention of novel words. Bilingual children accept two labels for an object (lexical overlap) for referent selection more than monolingual children, but in these previous studies, information about speakers’ language backgrounds was minimal. We investigated monolingual and bilingual 4-year-old children’s ability to apply mutual exclusivity and lexical overlap flexibly when objects were labelled either by one or two speakers with the same or different language backgrounds. We tested referent selection and retention of word–object mappings. Both language groups performed similarly for mutual exclusivity, were more likely to accept lexical overlap in the two-language than one-language condition, and performance was similar for referent selection and later retention. Monolingual and bilingual children can adapt their word-learning strategies to cope with the demands of different linguistic contexts.

This study explored monolingual and multilingual two- to five-year-olds’ reliance on a non-verbal and a verbal cue during word-referent mapping, in relation to vocabulary knowledge and, for the multilinguals, Dutch language exposure. Ninety monolingual and sixty-seven multilingual children performed a referential conflict experiment that pitted a non-verbal (pointing) cue and a verbal (mutual exclusivity) cue. Mixed-effect regressions showed no main effects of vocabulary and language exposure. An interaction between vocabulary and group showed that lower vocabulary scores were associated with a stronger reliance on pointing over mutual exclusivity for multilinguals (but not monolinguals). Furthermore, an interaction between vocabulary, language exposure, and cue word (novel vs. familiar label) indicated that multilinguals with lower exposure and lower vocabulary showed a stronger reliance on pointing over mutual exclusivity when a novel rather than familiar word was used. These findings suggest that multilingual and monolingual children go through different trajectories when learning to map words to referents.

How much information do language users need to differentiate potentially absolute synonyms into near-synonyms? How consistent must the information be? We present two simple experiments designed to investigate this. After exposure to two novel verbs, participants generalized them to positive or negative contexts. In Experiment 1, there was a tendency across conditions for the verbs to become differentiated by context, even following inconsistent, random, or neutral information about context during exposure. While a subset of participants matched input probabilities, a high proportion did not. As a consequence, the overall pattern was of growth in differentiation that did not closely track input distributions. Rather, there were two main patterns: When each verb had been presented consistently in a positive or negative context, participants overwhelmingly specialized both verbs in their output. When this was not the case, the verbs tended to become partially differentiated, with one becoming specialized and the other remaining less specialized. Experiment 2 replicated and expanded on Experiment 1 with the addition of a pragmatic judgment task and neutral contexts at test. Its results were consistent with Experiment 1 in supporting the conclusion that quality of input may be more important than quantity in the differentiation of synonyms.

During acquisition, children must learn both the meanings of words and how to interpret them in context. For example, children must learn the logical semantics of the scalar quantifier some and its pragmatically enriched meaning: ‘some but not all’. Some studies have shown that ‘scalar implicature’ – that some implies ‘some but not all’ – poses a challenge even to nine-year-olds, while others find success by age three. We asked whether reports of children's successes might be due to the computation of exclusion inferences (like contrast or mutual exclusivity) rather than scalar implicatures. We found that young children (N = 214; ages 4;0–7;11) sometimes compute symmetrical exclusion inferences rather than asymmetric scalar inferences. These data suggest that a stronger burden of evidence is required in studies of implicature; before concluding that children compute implicatures, researchers should first show that children exhibit sensitivity to asymmetric entailment in the task.

Mutual Exclusivity (ME) is a prominent constraint in language acquisition, which guides children to establish one-to-one mappings between words and referents. But how does unfolding experience of multiple-to-one word-meaning mappings in bilingual children's environment affect their understanding of when to use ME and when to accept lexical overlap? Three-to-five-year-old monolingual and simultaneous bilingual children completed two pragmatically distinct tasks, where successful word learning relied on either the default use of ME or the ability to accept overlapping labels. All children could flexibly use ME by following the social-pragmatic directions available in each task. However, linguistic experience shaped the development of ME use, whereby older monolinguals showed a greater reliance on the one-to-one mapping assumption, but older bilinguals showed a greater ability to accept lexical overlap. We suggest that flexible use of ME is thus shaped by pragmatic information present in each communicative interaction and children's individual linguistic experience.