Kriengwatana Buddhamas Pralle, Escudero Paola
Department of Psychology, University of Amsterdam, the Netherlands.
The MARCS Institute and ARC Centre of Excellence for the Dynamics of Language, Western Sydney University, Australia.
J Speech Lang Hear Res. 2017 Apr 14;60(4):1088-1093. doi: 10.1044/2016_JSLHR-H-16-0050.
This study tested an assumption of the Natural Referent Vowel (Polka & Bohn, 2011) framework, namely, that directional asymmetries in adult vowel perception can be influenced by language experience.
Data from participants reported in Escudero and Williams (2014) were analyzed. Spanish participants categorized the Dutch vowels /aː/ and /ɑ/ in 2 separate sessions: before and after vowel distributional training. Sessions were 12 months apart. Categorization was assessed using the XAB task, where on each trial participants heard 3 sounds sequentially (first X, then A, then B) and had to decide whether X was more similar to A or B.
Before training, participants exhibited a directional asymmetry in line with the prediction of Natural Referent Vowel. Specifically, Spanish listeners performed worse when the vowel change from X to A was a change from peripheral to central vowel (/ɑ/ to /aː/). However, this asymmetry was maintained 12 months later, even though distributional training improved vowel categorization performance.
Improvements in adult nonnative vowel categorization accuracy are not explained by attenuation of directional asymmetries. Directional asymmetries in vowel perception are altered during native language acquisition, but may possibly be impervious to nonnative language experiences in adulthood.
本研究检验了自然参照元音框架（波尔卡和博恩，2011年）的一个假设，即成人元音感知中的方向不对称性可能会受到语言经验的影响。
对埃斯库德罗和威廉姆斯（2014年）报告的参与者数据进行分析。西班牙参与者在两个不同阶段对荷兰元音/aː/和/ɑ/进行分类：元音分布训练之前和之后。两个阶段相隔12个月。使用XAB任务评估分类情况，在每次试验中，参与者依次听到3个声音（先是X，然后是A，再是B），并必须决定X与A还是B更相似。
训练前，参与者表现出与自然参照元音预测一致的方向不对称性。具体而言，当元音从X变为A是从外围元音变为央元音（/ɑ/变为/aː/）时，西班牙听众的表现更差。然而，尽管分布训练提高了元音分类表现，但这种不对称性在12个月后仍然存在。
成人非母语元音分类准确性的提高不能用方向不对称性的减弱来解释。元音感知中的方向不对称性在母语习得过程中会发生变化，但在成年期可能不受非母语语言经验的影响。
