One language or two? Navigating cross-language conflict in statistical word segmentation

Developmental changes in the word co-occurrences of Spanish-English bilingual children with and without developmental language disorder

PURPOSE

The study aimed to understand how bilingual children with typical language development (TLD) and those with developmental language disorder (DLD) use frequent word co-occurrences in their narratives.

METHOD

We studied the change over time in the word co-occurrences used by 30 Spanish-English bilingual children with and without DLD (experimental group). An additional normative group consisted of 98 TLD Spanish-English bilingual first graders. Children narrated two Spanish and two English stories in kindergarten and first grade. Employing a Python program on the transcribed narratives, we extracted all adjacent two-word and three-word co-occurrences. From the normative group, the 90 most frequently occurring two-word and 90 most frequently occurring three-word co-occurrences were extracted. The type and tokens of word co-occurrences each child in the experimental group produced out of the 180 identified word co-occurrences were analysed.

RESULT

Overall, children at first grade produced more word co-occurrences types than in kindergarten. Children with DLD used fewer types of word co-occurrences but produced them as often as than their TLD peers. Children with DLD increased their word co-occurrences from kindergarten to first grade at the same rate although at a lower frequency. Children in both groups produced similar types and tokens of word co-occurrences in both Spanish and English, except tokens of two word co-occurrences. Children produced two word co-occurrences more often in English than in their Spanish narratives.

CONCLUSION

The results shed light on children with DLD's deficits in production of word co-occurrences, indirectly reflecting possible deficits in statistical pattern detection.

Does bilingual experience influence statistical language learning?

Statistical language learning (SL) tasks measure different aspects of foreign language learning. Studies have used SL tasks to investigate whether bilingual experience confers advantages in acquiring additional languages through implicit processes. However, the results have been inconsistent, which may be related to bilingualism-related features (e.g., degree of dissimilarity between the specific language pair) and other variables such as specific processes that are targeted by the SL task. In the present study, we compared the performance of one Spanish monolingual and two bilingual (Spanish-Basque and Spanish-English) groups across three well-established SL tasks. Each task targeted a different aspect of foreign language learning; specifically, word segmentation, morphological rule generalization, and word-referent learning. In Experiment 1, we manipulated sub-lexical phonotactic patterns to vary the difficulty of three SL tasks, with the results showing no differences between the groups in word segmentation. In Experiment 2, we included non-adjacent dependencies to target affixal morphology rule learning, but again no group-related differences were found. In Experiment 3, we addressed word learning using an audio-visual SL task combining exclusive and multiple word-referent mappings, and found that bilinguals outperformed monolinguals, suggesting that bilingualism may exert influences on SL at the lexical level. This advantage might have been mediated by the high working memory demands required to perform the task. Summarizing, this study shows no evidence for a general bilingual advantage in SL, although bilinguals may outperform monolinguals under specific experimental conditions such as SL tasks that place high demands on working memory processes. In addition, the similar performance of Spanish-Basque and Spanish-English bilinguals across all three SL tasks suggests that the degree of dissimilarity between pairs of spoken languages does not modulate SL skills.

Statistical word segmentation: Anchoring learning across contexts

The present experiments were designed to assess infants' abilities to use syllable co-occurrence regularities to segment fluent speech across contexts. Specifically, we investigated whether 9-month-old infants could use statistical regularities in one speech context to support speech segmentation in a second context. Contexts were defined by different word sets representing contextual differences that might occur across conversations or utterances. This mimics the integration of information across multiple interactions within a single language, which is critical for language acquisition. In particular, we performed two experiments to assess whether a statistically segmented word could be used to anchor segmentation in a second, more challenging context, namely speech with variable word lengths. The results of Experiment 1 were consistent with past work suggesting that statistical learning may be hindered by speech with word-length variability, which is inherent to infants' natural speech environments. In Experiment 2, we found that infants could use a previously statistically segmented word to support word segmentation in a novel, challenging context. We also present findings suggesting that this ability was associated with infants' early word knowledge but not their performance on a cognitive development assessment.