More Like this

1. Do Infants Really Learn Phonetic Categories?

   https://doi.org/10.1162/opmi_a_00046  

   Feldman, Naomi H.; Goldwater, Sharon; Dupoux, Emmanuel; Schatz, Thomas (January 2021, Open Mind)

   null (Ed.)

   Abstract Early changes in infants’ ability to perceive native and nonnative speech sound contrasts are typically attributed to their developing knowledge of phonetic categories. We critically examine this hypothesis and argue that there is little direct evidence of category knowledge in infancy. We then propose an alternative account in which infants’ perception changes because they are learning a perceptual space that is appropriate to represent speech, without yet carving up that space into phonetic categories. If correct, this new account has substantial implications for understanding early language development. 

   more » « less
2. Don't force it! Gradient speech categorization calls for continuous categorization tasks

   https://doi.org/10.1121/10.0015201  

   Apfelbaum, Keith S.; Kutlu, Ethan; McMurray, Bob; Kapnoula, Efthymia C. (December 2022, The Journal of the Acoustical Society of America)

   Research on speech categorization and phoneme recognition has relied heavily on tasks in which participants listen to stimuli from a speech continuum and are asked to either classify each stimulus (identification) or discriminate between them (discrimination). Such tasks rest on assumptions about how perception maps onto discrete responses that have not been thoroughly investigated. Here, we identify critical challenges in the link between these tasks and theories of speech categorization. In particular, we show that patterns that have traditionally been linked to categorical perception could arise despite continuous underlying perception and that patterns that run counter to categorical perception could arise despite underlying categorical perception. We describe an alternative measure of speech perception using a visual analog scale that better differentiates between processes at play in speech categorization, and we review some recent findings that show how this task can be used to better inform our theories. 

   more » « less
3. A reinforcement learning approach to speech category acquisition

   Thorburn, Craig; Lau, Ellen; Feldman, Naomi (January 2022, Proceedings of the Annual Boston University Conference on Language Development)

   Adults struggle to learn non-native speech categories in many experimental settings (Goto, 1971), but learn efficiently in a video game paradigm where non-native speech sounds have functional significance (Lim and Holt, 2011). Behavioral and neural evidence from this and other paradigms point toward the involvement of reinforcement learning mechanisms in speech category learning. We formalize this hypothesis computationally and present two simulations. The first simulates the findings of Lim et al. (2019), providing proof in principle that a reinforcement learning algorithm can successfully capture human results in a video game where people are learning novel categories of noise tokens. Our second simulation extends this to speech sounds and demonstrates that our algorithm mimics second language learners’ improvement on discrimination of a non-native speech contrast. Together these two simulations show that reinforcement learning provides an accurate model of human learning in this paradigm and provide evidence supporting the hypothesis that this mechanism could play a key role in effective speech category learning in adults. Being able to identify the algorithms employed in this paradigm could provide many avenues for pedagogical changes in second language learning and let teachers harness the processes that allow for efficient learning and improvement of non-native perceptual ability. 

   more » « less
4. Moving away from deficiency models: Gradiency in bilingual speech categorization

   https://doi.org/10.3389/fpsyg.2022.1033825  

   Kutlu, Ethan; Chiu, Samantha; McMurray, Bob (November 2022, Frontiers in Psychology)

   For much of its history, categorical perception was treated as a foundational theory of speech perception, which suggested that quasi-discrete categorization was a goal of speech perception. This had a profound impact on bilingualism research which adopted similar tasks to use as measures of nativeness or native-like processing, implicitly assuming that any deviation from discreteness was a deficit. This is particularly problematic for listeners like heritage speakers whose language proficiency, both in their heritage language and their majority language, is questioned. However, we now know that in the monolingual listener, speech perception is gradient and listeners use this gradiency to adjust subphonetic details, recover from ambiguity, and aid learning and adaptation. This calls for new theoretical and methodological approaches to bilingualism. We present the Visual Analogue Scaling task which avoids the discrete and binary assumptions of categorical perception and can capture gradiency more precisely than other measures. Our goal is to provide bilingualism researchers new conceptual and empirical tools that can help examine speech categorization in different bilingual communities without the necessity of forcing their speech categorization into discrete units and without assuming a deficit model. 

   more » « less
5. ADVANCING THE STATE OF THE ART IN L2 SPEECH PERCEPTION-PRODUCTION RESEARCH: REVISITING THEORETICAL ASSUMPTIONS AND METHODOLOGICAL PRACTICES

   https://doi.org/10.1017/S0272263121000371  

   Nagle, Charles L.; Baese-Berk, Melissa M. (January 2021, Studies in Second Language Acquisition)

   null (Ed.)

   Abstract One of the basic goals of second language (L2) speech research is to understand the perception-production link, or the relationship between L2 speech perception and L2 speech production. Although many studies have examined the link, they have done so with strikingly different conceptual foci and methods. Even studies that appear to use similar perception and production tasks often present nontrivial differences in task characteristics and implementation. This conceptual and methodological variation makes meaningful synthesis of perception-production findings difficult, and it also complicates the process of developing new perception-production models that specifically address how the link changes throughout L2 learning. In this study, we scrutinize theoretical and methodological issues in perception-production research and offer recommendations for advancing theory and practice in this domain. We focus on L2 sound learning because most work in the area has focused on segmental contrasts. 

   more » « less