Max Planck Institute for Psycholinguistics, Nijmegen, Netherlands.
Lancaster University, Lancaster, United Kingdom.
PLoS One. 2020 Dec 17;15(12):e0243436. doi: 10.1371/journal.pone.0243436. eCollection 2020.
High frequency words play a key role in language acquisition, with recent work suggesting they may serve both speech segmentation and lexical categorisation. However, it is not yet known whether infants can detect novel high frequency words in continuous speech, nor whether they can use them to help learning for segmentation and categorisation at the same time. For instance, when hearing "you eat the biscuit", can children use the high-frequency words "you" and "the" to segment out "eat" and "biscuit", and determine their respective lexical categories? We tested this in two experiments. In Experiment 1, we familiarised 12-month-old infants with continuous artificial speech comprising repetitions of target words, which were preceded by high-frequency marker words that distinguished the targets into two distributional categories. In Experiment 2, we repeated the task using the same language but with additional phonological cues to word and category structure. In both studies, we measured learning with head-turn preference tests of segmentation and categorisation, and compared performance against a control group that heard the artificial speech without the marker words (i.e., just the targets). There was no evidence that high frequency words helped either speech segmentation or grammatical categorisation. However, segmentation was seen to improve when the distributional information was supplemented with phonological cues (Experiment 2). In both experiments, exploratory analysis indicated that infants' looking behaviour was related to their linguistic maturity (indexed by infants' vocabulary scores) with infants with high versus low vocabulary scores displaying novelty and familiarity preferences, respectively. We propose that high-frequency words must reach a critical threshold of familiarity before they can be of significant benefit to learning.
高频词在语言习得中起着关键作用，最近的研究表明，它们可能同时服务于语音分割和词汇分类。然而，目前还不清楚婴儿是否能在连续的语音中检测到新的高频词，也不清楚他们是否能同时利用它们来帮助分割和分类学习。例如，当听到“你吃饼干”时，孩子们能否使用高频词“你”和“那个”将“吃”和“饼干”分割出来，并确定它们各自的词汇类别？我们在两个实验中对此进行了测试。在实验 1 中，我们让 12 个月大的婴儿熟悉由目标词重复组成的人工语音，这些目标词之前有高频标记词，将目标词分为两个分布类别。在实验 2 中，我们使用相同的语言重复了这项任务，但增加了语音线索来表示单词和类别结构。在这两项研究中，我们通过对分割和分类的头转偏好测试来衡量学习效果，并将表现与听到没有标记词的人工语音的对照组（即只有目标词）进行比较。没有证据表明高频词有助于语音分割或语法分类。然而，当分布信息辅以语音线索时，分割得到了改善（实验 2）。在这两个实验中，探索性分析表明，婴儿的注视行为与其语言成熟度（以婴儿的词汇分数为指标）有关，词汇分数高的婴儿与词汇分数低的婴儿分别表现出新奇和熟悉偏好。我们提出，高频词必须达到一定的熟悉度阈值，才能对学习产生显著的益处。
