Enhanced explicit vocabulary learning compared to implicit grammar learning in adults

Compared to young children, the language learning process is much more difficult and less successful in adulthood. Little is known about how non-linguistic cognitive processes contribute to these age-dependent differences. We argue that language learning involves both explicit declarative memory processes to learn vocabulary and implicit procedural memory processes to learn grammatical patterns. In this preliminary study, we aimed to quantify the relative contribution of declarative versus procedural learning in adults via an artificial language learning task. Participants ages 18 to 29 heard novel singular and plural words associated with images of common objects. The grammar of the language consisted of two regular suffixes that marked plurality intermixed with irregular words containing irregular suffixes. After 30 minutes of training, participants were then tested on whether an auditorily-presented word correctly matched a corresponding object. Vocabulary was tested using regular singular and irregular plural words learned in the training sessions while grammar was tested by generalizing the grammatical plural suffixes to novel words and forms of words that did not appear in training. Results revealed that adults performed significantly better and quicker on vocabulary test items compared to grammar test items. This suggests that adults’ diminished engagement in procedural mechanisms may result in less effective grammar learning. Overall, the results shed light on how declarative and procedural memory differences result in adults’ specific difficulty with grammatical language learning in a domain-general manner. Ongoing research in our laboratory is examining the neural bases of this phenomenon using the present language learning paradigm

Sensitivity of human auditory cortex to rapid frequency modulation revealed by multivariate representational similarity analysis.

Functional Magnetic Resonance Imaging (fMRI) was used to investigate the extent, magnitude, and pattern of brain activity in response to rapid frequency-modulated sounds. We examined this by manipulating the direction (rise vs. fall) and the rate (fast vs. slow) of the apparent pitch of iterated rippled noise (IRN) bursts. Acoustic parameters were selected to capture features used in phoneme contrasts, however the stimuli themselves were not perceived as speech per se. Participants were scanned as they passively listened to sounds in an event-related paradigm. Univariate analyses revealed a greater level and extent of activation in bilateral auditory cortex in response to frequency-modulated sweeps compared to steady-state sounds. This effect was stronger in the left hemisphere. However, no regions showed selectivity for either rate or direction of frequency modulation. In contrast, multivoxel pattern analysis (MVPA) revealed feature-specific encoding for direction of modulation in auditory cortex bilaterally. Moreover, this effect was strongest when analyses were restricted to anatomical regions lying outside Heschl\u27s gyrus. We found no support for feature-specific encoding of frequency modulation rate. Differential findings of modulation rate and direction of modulation are discussed with respect to their relevance to phonetic discrimination

Statistical Learning Across Visual and Auditory Modalities

Our ability to learn language is accomplished by using structural patterns found in everyday language. We use these structural patterns in language through a process of Statistical Learning (SL) to implicitly predict sequences in speech and visual input. Our research explored how SL predicts patterns of auditory and visual learning in adults (N = 40; M = 27.1 years) to provide a more complete picture of SL. For the auditory task, participants were tested on whether they learned a novel language that they passively listened to for 6 minutes. Implicit and explicit learning were assessed after the exposure phase. For the visual task, participants were tasked with rapidly indicating a target’s spatial location, which would appear in one of four circles. Reaction time and accuracy were assessed to determine whether implicit and explicit SL occurred. Results demonstrated that implicit SL occurred in both modalities; however, no explicit learning occurred in the visual task and no correlations were found between these tasks. These results hint to an underlying difference in auditory and visual SL. This data may support the hypothesis that SL is modality specific and is not governed by a more general processing capacity. These results provide behavioural data on the role of SL across modalities, which can inform theories of the neurocognitive underpinnings of language and reading acquisition. To better understand the role that SL has on reading and language abilities, future research should look at visual and auditory SL in children with reading and language impairments

Learning unfamiliar words and perceiving non-native vowels in a second language: Insights from eye tracking

One of the challenges in second-language learning is learning unfamiliar word forms, especially when this involves novel phoneme contrasts. The present study examines how real-time processing of newly-learned words and phonemes in a second language is impacted by the structure of learning (discrimination training) and whether asking participants to complete the same task after a 16–21 h delay favours subsequent word recognition. Specifically, using a visual world eye tracking paradigm, we assessed how English listeners processed newly-learned words containing non-native French front-rounded [y] compared to native-sounding vowels, both immediately after training and the following day. Some learners were forced to discriminate between vowels that are perceptually similar for English listeners, [y]-[u], while others were not. We found significantly better word-level processing on a variety of indices after an overnight delay. We also found that training [y] words paired with [u] words (vs. [y]-Control pairs) led to a greater decrease in reaction times during the word recognition task over the two testing sessions. Discrimination training using perceptually similar sounds had facilitative effects on second language word learning with novel phonemic information, and real-time processing measures such as eyetracking provided valuable insights into how individuals learn words and phonemes in a second language

Eyetracking of coarticulatory cue responses in children and adults

Prior work suggests listeners are sensitive to coarticulatory cues during spoken word recognition; however, little is known about how this ability develops in children. In the present study, children and adults listened to words containing congruent and incongruent coarticulatory cues while looking at a two-picture display. We manipulated the congruency of the auditory-coarticulatory information such that the initial phoneme of the auditory cue matched the target, or contained an incongruent initial phoneme that instead matched the distractor picture. Accordingly, we observed both slower rates of looks to the target and higher rates of looks to the distractor on incongruent trials, indicating that both children and adults were sensitive to coarticulatory congruency. These findings suggest that children maintain detailed phonological representations of words, and may use coarticulatory information to facilitate spoken word recognition

Language dominance modulates the perception of spanish approximants in late bilinguals

© 2020 by the authors. The ability to discriminate phonetically similar first language (L1) and second language (L2) sounds has significant consequences for achieving target-like proficiency in second-language learners. This study examines the L2 perception of Spanish approximants [Β, δ, γ] in comparison with their voiced stop counterparts [b, d, g] by adult English-Spanish bilinguals. Of interest is how perceptual effects are modulated by factors related to language dominance, including proficiency, language history, attitudes, and L1/L2 use, as measured by the Bilingual Language Profile questionnaire. Perception of target phones was assessed in adult native Spanish speakers (n = 10) and Spanish learners (n = 23) of varying proficiency levels, via (vowel-consonant-vowel) VCV sequences featuring both Spanish approximants and voiced stops during an AX discrimination task. Results indicate a significant positive correlation between perceptual accuracy and a language dominance score. Findings further demonstrate a significant hierarchy of increasing perceptual difficulty: Β \u3c δ \u3c γ. Through an examination of bilingual language dominance, composed of the combined effects of language history, use, proficiency, and attitudes, the present study contributes a more nuanced and complete examination of individual variables that affect L2 perception, reaching beyond proficiency and experience alone

Specific language or working memory impairments: A small scale observational study

Study of the developmental relationship between language and working memory skills has only just begun, despite the prominent role of their interdependency in some theoretical accounts of developmental language impairments. Recently, Archibald and Joanisse (2009) identified children with specific language impairment (SLI), or specific working memory impairment (SWMI), or mixed language and working memory impairment (Mixed) based on standardized testing. In the present study, we report a first effort to provide clinical verification of these profiles by describing the social, behavioral, and academic characteristics of individual group members. Two each of children with SLI, SWMI, or Mixed impairments, individually paired with six typically developing classmates, were observed in their classroom, and their teachers completed questionnaires related to communication, working memory, and attention. Children with impairments were distinguished from typically developing children; however, relatively few patterns further distinguished the children with SLI, SWMI, and Mixed impairments. Interestingly, the children with memory impairments were found to have some language-related difficulties, and the children with language impairments, some memory-related difficulties. The limitations of these preliminary findings and future directions are discussed. © The Author(s) 2011