Learning word order: early beginnings.

We examine the beginning of the acquisition of the relative order of function and content words, a fundamental but cross-linguistically highly variable aspect of grammar. A review of the existing empirical literature shows that infants as young as 8 months of age can distinguish between functors and content words, and have a rudimentary knowledge of the order of these two universal lexical categories in their native language. Furthermore, human adults and non-human animals such as rodents process the same linguistic information differently from infants, emphasizing the developmental relevance of bootstrapping function/content word order from surface cues available in the input. We discuss the implications of these findings for a synergistic view of language acquisition, considering how grammar acquisition interacts with word learning.

8-month-old infants' ability to process word order is shaped by the amount of exposure.

In the majority of languages, the functional distinction between functors and content words correlates with lower-level, perceptually observable properties. Functors are generally more frequent and prosodically more minimal than content words. Previous studies demonstrate that the frequency distribution and the different acoustic realization of frequent and infrequent words guide infants in discovering their native word order. However, whether and if yes, how the exact frequency ratio impacts infants' ability to recognize function and content words and their relative order has never been explored. Here we investigate this by testing whether with a small ratio between functors' and content words' frequency, 1:3 as opposed to the 1:9 ratio in previous studies, French 8-month-olds are able to establish the functor-initial word order typical of their native language (Experiment 1) and whether prosody (Experiment 2) and the amount of exposure (Experiment 3) modulate this ability. We observed that infants exhibited the predicted functor-initial preference only when they were exposed to a short familiarization phase, i.e. reduced exposure. This suggests that different amounts of information selectively trigger different processing mechanisms, and little exposure may favor the extraction of regularities.

A multi-lab study of bilingual infants: Exploring the preference for infant-directed speech.

From the earliest months of life, infants prefer listening to and learn better from infant-directed speech (IDS) than adult-directed speech (ADS). Yet, IDS differs within communities, across languages, and across cultures, both in form and in prevalence. This large-scale, multi-site study used the diversity of bilingual infant experiences to explore the impact of different types of linguistic experience on infants' IDS preference. As part of the multi-lab ManyBabies 1 project, we compared lab-matched samples of 333 bilingual and 385 monolingual infants' preference for North-American English IDS (cf. ManyBabies Consortium, 2020: ManyBabies 1), tested in 17 labs in 7 countries. Those infants were tested in two age groups: 6-9 months (the younger sample) and 12-15 months (the older sample). We found that bilingual and monolingual infants both preferred IDS to ADS, and did not differ in terms of the overall magnitude of this preference. However, amongst bilingual infants who were acquiring North-American English (NAE) as a native language, greater exposure to NAE was associated with a stronger IDS preference, extending the previous finding from ManyBabies 1 that monolinguals learning NAE as a native language showed a stronger preference than infants unexposed to NAE. Together, our findings indicate that IDS preference likely makes a similar contribution to monolingual and bilingual development, and that infants are exquisitely sensitive to the nature and frequency of different types of language input in their early environments.

Word Frequency Is a Cue to Lexical Category for 8-Month-Old Infants.

The linguistic distinction between function words (functors) (e.g., the, he, that, on…), signaling grammatical structure, and content words (e.g., house, blue, carry…), carrying meaning, is universal across the languages of the world. These two lexical categories also differ in their phonological makeup (functors being shorter and more minimal) and frequency of occurrence (individual functors being much more frequent than most content words). The frequency-based discrimination of the two categories could constitute a powerful mechanism for infants to acquire the basic building blocks of language. As functors constitute closed classes and content words come in open classes, we examined whether 8-month-old monolingual infants relied on word frequency to categorize and track functors and content words. In six artificial grammar-learning experiments, we have found that infants process frequent words as belonging to closed classes, and infrequent words as belonging to open classes, and they map the relative order of these categories following the basic word order of their native language. These findings provide the earliest evidence that infants use word frequency as a cue to lexical categories and combine them to build rudimentary representations of grammar.

The Novelty Effect as a Predictor of Language Outcome.

A controversial issue in the field of language acquisition is the extent to which general attentional or cognitive abilities play a role in individual differences in early language outcomes. Here we report a longitudinal study where we examined whether processing efficiency in a novelty detection task predicted later vocabulary size in a stable manner across time. We found that the novelty detection ability measured at 9 months was significantly predictive of later vocabulary size at 12, 14, 18, and 24 months. This study, therefore, emphasizes the importance of controlling for non-linguistic factors when assessing individual variability in language development. A more accurate assessment of language development may be obtained if general attentional and cognitive abilities are also taken into account in addition to linguistic factors.

Listening natively across perceptual domains?

Our native tongue influences the way we perceive other languages. But does it also determine the way we perceive nonlinguistic sounds? The authors investigated how speakers of Italian, Turkish, and Persian group sequences of syllables, tones, or visual shapes alternating in either frequency or duration. We found strong native listening effects with linguistic stimuli. Speakers of Italian grouped the linguistic stimuli differently from speakers of Turkish and Persian. However, speakers of all languages showed the same perceptual biases when grouping the nonlinguistic auditory and the visual stimuli. The shared perceptual biases appear to be determined by universal grouping principles, and the linguistic differences caused by prosodic differences between the languages. Although previous findings suggest that acquired linguistic knowledge can either enhance or diminish the perception of both linguistic and nonlinguistic auditory stimuli, we found no transfer of native listening effects across auditory domains or perceptual modalities. (PsycINFO Database Record