DEVELOPMENT OF PHONETIC CATEGORIES

人们普遍认为，第二语言存在一个关键期 (二)言语学习。然而，外国口音的实际原因(S) 仍然不确定。这里提出的研究将评估一个模型，该模型 试图解释双语者年龄相关的生产和生产的变化 第二语言中的元音和辅音(“发音”)的知觉 母语(L1)。L2中的分段生产错误是重要的 因为它们导致误解和/或处理速度减慢，以及 助长负面的个人评价。一种不那么明显的，但 然而，L1和L2语音差异的严重后果是 节段性知觉错误导致脑干听觉障碍 理解第二语言。这种错误可能是由于神经系统的变化引起的。 这降低了添加或修改感觉运动程序的能力，或者 防止对未找到的声音形成知觉表征 在L1。断定分段生产的原因(S) 知觉错误在临床上具有重要意义。例如，如果它们出现 因为成熟的神经可塑性限制或 感觉运动灵活性，然后减少外国口音的好处 治疗，或对那些遭受脑创伤的人进行语言治疗，可能 对于已度过关键时期的个人，严格限制。 另一方面，如果老化仅仅导致对完整的 学习机制，那么新的努力必须针对确定 如何才能最好地构建治疗以优化成年人的能力。 根据正在评估的模型，外国口音的出现是因为 说两种语言的人不能有效地分离他们的声音系统 两种语言。该模型预测了产生错误的三个来源 L2发音：(L)与相邻L1发音的属性部分合并 在L2和L1发音持续链接的情况下 感觉上；(2)不正确的特征规范，在以下情况下 L2使用与L1不同的特征或特征权重；以及(3) 当一个新的类别已经被 形成了。九个实验将测试意语-英语的表现 或者主要根据年龄的不同而不同的日英双语者 学习(美国在线)英语。假设，错误类型的频率#L 2号错误将随着AOL的增加而增加，而3号错误类型将减少 随着双语者AOL的增加，出现的频率也会增加。三个拟议的实验 将定义L1中元音之间的声学和知觉关系 和L2。另一项是评估双语者输出第一语言的准确性 和二语元音，并测试元音类别的形成 使用分类辨别任务的英语。其他实验将会 使用类似的技术来检查生产和感知 辅音。一个令人感兴趣的问题是，双语者是否正确地 在形成的第一语言清单中找不到产生的英语辅音 英语辅音的分类，而产生辅音的双语者 英语辅音错误地没有形成它们的类别。两个人 其余的实验将评估AOL和 双语者在感知英语元音和英语元音时使用非母语特征 辅音。

It is widely believed that a critical period exists for second-language (L2) speech learning. However, the actual cause(s) of foreign accent remain uncertain. The research proposed here will evaluate a model that attempts to account for age-related changes in bilinguals' production and perception of vowels and consonants ("sounds") in their L2 and in their native language (L1). Segmental production errors in the L2 are important because they result in misunderstandings and/or slowed processing, and contribute to negative personal evaluations. A less obvious, but nevertheless serious consequence of L1 vs L2 phonological differences are segmental perception errors that contribute to difficulties in comprehending the L2. Such errors might arise from neurological changes that diminish the ability to add or modify sensorimotor programs, or prevent the formation of perceptual representations for sounds not found in the L1. Deter-mining the cause(s) of segmental production and perception errors is important clinically. For example, if they arise because of maturationally determined limits on neural plasticity or sensorimotor flexibility, then the benefit of foreign accent reduction therapy, or speech therapy for those who have suffered brain trauma, may be severely limited for individuals who have passed the critical period. On the other hand, if aging merely results in a non-optimal use of intact learning mechanisms, then renewed effort must be directed at determining how therapy can best be structured to optimize adults' capabilities. According to the model under evaluation, foreign accents arise because bilinguals are unable to separate effectively the sound systems of their two languages. The model predicts three sources of error in producing an L2 sound: (l) Partial merger with the properties of a neighboring L1 sound in instances where the L2 and L1 sounds persist in being linked perceptually; (2) Incorrect featural specification, in instances where the L2 uses different features or feature weights than the L1; and (3) Deflection away from a neighboring L1 sound when a new category has been formed. Nine experiments will examine the performance of Italian-English or Japanese-English bilinguals who differ primarily according to their age of learning (AOL) English. By hypothesis, the frequency of error types #l and #2 will increase as AOL increases whereas error type #3 will decrease in frequency as the bilinguals' AOL increases. Three proposed experiments will define the acoustic and perceptual relation between the vowels in L1 and L2. Another will assess the accuracy with which bilinguals produce L1 and L2 vowels, and test for the formation of categories for vowels in English using a categorical discrimination task. Other experiments will use similar techniques to examine the production and perception of consonants. One question of interest is whether bilinguals who correctly produced English consonants not found in the L1 inventory formed categories for the English consonants whereas bilinguals who produced the English consonants incorrectly did not form categories for them. The two remaining experiments will assess the relation between AOL and the bilinguals' use of non-L1 features in perceiving English vowels and consonants.