On the Difficulty of Defining “Difficult” in Second-Language Vowel Acquisition
On the Difficulty of Defining “Difficult” in Second-Language Vowel Acquisition
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论二语元音习得中“难”的界定
DOI：
10.3389/fcomm.2021.639398
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发表时间：
2021
影响因子：
2.4
通讯作者：
M. Munro
中科院分区：
文献类型：
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作者：
M. Munro
第二语言（L2）音韵学的难度等级长期以来在学习模型的假设和评估中发挥着作用。在第二语言发音教学中，层次结构被认为有助于根据预期的困难领域制定教学策略。这项研究探讨了为粤语使用者发出的英语时态和宽松闭元音 (/i I u ʊ/) 定义一个教学上有用的难度等级的实用性。与英语对应词不同，粤语的紧松松弛对是异音变体，[i u] 出现在齿龈之前，[I ʊ] 出现在软腭之前。每个时态-松弛对代表一种“音素分裂”，其中单个 L1 类别的成员在 L2 中以对比方式实现。尽管有证据表明英语时态-宽松的区别对于说粤语的人来说是一个挑战，但之前的实证研究还没有从跨多个语音上下文和共享相同韵律的不同单词的元音可懂度的角度仔细考虑这个问题。在一项基于图片的单词启发任务中，18 名讲粤语的参与者产生了 31 个高频 CV 和 CVC 单词。由经过语音训练的法官评估元音的清晰度。对分数拟合了一系列混合效应二元逻辑模型，以元音质量、语音上下文（韵律）和单词作为因子，以加拿大居住时间和日常英语使用作为协变量。正如预期的那样，出现的元音的一般难度等级（/i/>/u/>/ʊ/>/I/）由于语音上下文之间的巨大差异而变得复杂。结果在转移方面不容易解释；此外，具有相同韵律的不同单词的清晰度也不尽相同。最严重的建模并发症是说话者之间在困难方面存在很大的差异，这无法通过模型协变量来解释。尽管一些困难在群体层面上大致是系统性的，但有人认为，根据这些数据建立一个教学上有用的层次结构将被证明是棘手的。相反，第二语言学习者可能会通过针对其个人问题领域的评估和教学目标获得更好的服务，而不是关注从难度等级预测的错误。
Hierarchies of difficulty in second-language (L2) phonology have long played a role in the postulation and evaluation of learning models. In L2 pronunciation teaching, hierarchies are assumed to be helpful in the development of instructional strategies based on anticipated areas of difficulty. This investigation addressed the practicality of defining a pedagogically useful hierarchy of difficulty for English tense and lax close vowels (/i I u ʊ/) produced by Cantonese speakers. Unlike their English counterparts, Cantonese close tense-lax pairs are allophonic variants with [i u] occurring before alveolars and [I ʊ] before velars. Each tense-lax pair represents a “phonemic split” in which members of a single L1 category are realized contrastively in L2. Despite evidence that English tense-lax distinctions are challenging for Cantonese speakers, no previous empirical work has closely considered the problem from the standpoint of vowel intelligibility across multiple phonetic contexts and in different words sharing the same rhyme. In a picture-based word-elicitation task, 18 Cantonese-speaking participants produced 31 high-frequency CV and CVC words. Vowels were evaluated for intelligibility by phonetically-trained judges. A series of mixed-effects binary logistic models were fitted to the scores, with vowel quality, phonetic context (rhyme) and word as factors, and length of Canadian residence and daily use of English as co-variates. As expected, the general hierarchy of difficulty for vowels that emerged (/i/ > /u/ > /ʊ/ > /I/) was complicated by large differences across phonetic contexts. Results were not readily explicable in terms of transfer; moreover, different words with the same rhyme were not produced with equal intelligibility. The most serious modeling complication was the sizeable inter-speaker variability in difficulties, which could not be accounted for by model co-variates. Although some difficulties were roughly systematic at the group level, it is argued that establishing a pedagogically useful hierarchy on such data would prove intractable. Rather, L2 learners might be better served by assessment and instructional targeting of their individual problem areas than by a focus on errors predicted from hierarchies of difficulty.