Cummings Alycia E, Ogiela Diane A, Wu Ying C
Department of Communication Sciences and Disorders, Idaho State University, Meridian, ID, United States.
Swartz Center for Computational Neuroscience, University of California, San Diego, San Diego, CA, United States.
Front Hum Neurosci. 2020 Dec 22;14:580697. doi: 10.3389/fnhum.2020.580697. eCollection 2020.
The Featurally Underspecified Lexicon (FUL) theory predicts that [coronal] is the language universal default place of articulation for phonemes. This assumption has been consistently supported with adult behavioral and event-related potential (ERP) data; however, this underspecification claim has not been tested in developmental populations. The purpose of this study was to determine whether children demonstrate [coronal] underspecification patterns similar to those of adults. Two English consonants differing in place of articulation, [labial] /b/ and [coronal] /d/, were presented to 24 children (ages 4-6 years) characterized by either a typically developing phonological system (TD) or a phonological disorder (PD). Two syllables, /bɑ/ and /dɑ/, were presented in an ERP oddball paradigm where both syllables served as the standard and deviant stimulus in opposite stimulus sets. Underspecification was examined with three analyses: traditional mean amplitude measurements, cluster-based permutation tests, and single-trial general linear model (GLM) analyses of single-subject data. Contrary to previous adult findings, children with PD demonstrated a large positive mismatch response (PMR) to /bɑ/ while the children with TD exhibited a negative mismatch response (MMN); significant group differences were not observed in the /dɑ/ responses. Moreover, the /bɑ/ deviant ERP response was significantly larger in the TD children than in the children with PD. At the single-subject level, more children demonstrated mismatch responses to /dɑ/ than to /bɑ/, though some children had a /bɑ/ mismatch response and no /dɑ/ mismatch response. While both groups of children demonstrated similar responses to the underspecified /dɑ/, their neural responses to the more specified /bɑ/ varied. These findings are interpreted within a proposed developmental model of phonological underspecification, wherein children with PD are functioning at a developmentally less mature stage of phonological acquisition than their same-aged TD peers. Thus, phonological underspecification is a phenomenon that likely develops over time with experience and exposure to language.
特征未充分指定词汇（FUL）理论预测，[冠状音]是音素在语言中普遍默认的发音部位。这一假设一直得到成人行为和事件相关电位（ERP）数据的支持；然而，这一未充分指定的说法尚未在发育人群中得到验证。本研究的目的是确定儿童是否表现出与成人相似的[冠状音]未充分指定模式。研究人员向24名儿童（4至6岁）呈现了两个发音部位不同的英语辅音，[唇音] /b/和[冠状音] /d/，这些儿童要么具有典型发育的语音系统（TD），要么患有语音障碍（PD）。在ERP奇偶数范式中呈现了两个音节，/bɑ/和/dɑ/，其中两个音节在相反的刺激组中分别作为标准刺激和偏差刺激。通过三种分析来检验未充分指定情况：传统的平均振幅测量、基于聚类的置换检验以及对单受试者数据的单试验通用线性模型（GLM）分析。与之前成人的研究结果相反，患有PD的儿童对/bɑ/表现出较大的正失配反应（PMR），而患有TD的儿童表现出负失配反应（MMN）；在/dɑ/反应中未观察到显著的组间差异。此外，TD儿童中/bɑ/偏差ERP反应明显大于患有PD的儿童。在单受试者水平上，更多儿童对/dɑ/表现出失配反应，而不是对/bɑ/，尽管有些儿童对/bɑ/有失配反应，而对/dɑ/没有失配反应。虽然两组儿童对未充分指定的/dɑ/表现出相似的反应，但他们对更明确的/bɑ/的神经反应有所不同。这些发现是在一个提出的语音未充分指定发育模型中进行解释的，其中患有PD的儿童在语音习得方面的发育阶段比同龄的TD儿童更不成熟。因此，语音未充分指定是一种可能随着时间推移通过经验和接触语言而发展的现象。
