This study used speech resynthesis to manipulate vowel formant frequencies in natural speech stimuli to examine the influence of magnitude and direction of spectral deviation from native norms, as well as the proximity of adjacent categories, on foreign-accentedness ratings, comprehensibility ratings and vowel identification. Experiment 1 contrasted the impact of spectral deviation on peripheral and non-peripheral vowels by shifting the first and second formant center frequencies in English vowels /ɔ/, /ʌ/, /ɛ/, /ɑ/, and /æ/ toward the acoustically closest vowel, and either the next-closest vowel, or unoccupied vowel space. To directly compare the impact of different deviation directions and proximity of adjacent categories without being confounded by F1–F2 variability within the individual vowel, formant frequencies in one English vowel, /ɑ/, were manipulated in Experiment 2 toward the four cardinal and four intercardinal directions. Across both experiments, spectral deviation that increased overlap with adjacent categories reduced comprehensibility, and increased both accentedness and misidentification. Neither the direction nor the magnitude of spectral deviations from native norms alone were sufficient to account for task performance. These findings imply that vowel space dispersion, specifically location within vowel space, plays a role in both accentedness judgments and vowel identification.

这项研究使用语音再合成来控制自然语音刺激中的元音共振峰频率，以检查频谱偏离自然规范的幅度和方向以及邻近类别的邻近度对外来重音等级，可理解性等级和元音识别的影响。实验1通过将英语元音中的第一和第二共振峰中心频率/ɔ/，/ɑ/，///，/ɑ/和/æ/移向声学方向，对比了频谱偏差对外围和非外围元音的影响最接近的元音，以及最接近的元音或未占用的元音空间。为了直接比较不同偏离方向和相邻类别的接近度的影响，而不会被单个元音中的F1-F2变异所混淆，一个英语元音中的共振峰频率/ frequencies /，在实验2中朝四个主方向和四个主心间方向操作。在两个实验中，与相邻类别重叠增加的光谱偏差降低了可理解性，并增加了重音和误识别。频谱偏离自然准则的方向和幅度都不足以说明任务的执行情况。这些发现暗示元音空间的分散，特别是元音空间内的位置，在重音判断和元音识别中都起着作用。频谱偏离自然准则的方向和幅度都不足以说明任务的执行情况。这些发现暗示元音空间的分散，特别是元音空间内的位置，在重音判断和元音识别中都起着作用。频谱偏离自然准则的方向或幅度都不足以说明任务的执行情况。这些发现暗示元音空间的分散，特别是元音空间内的位置，在重音判断和元音识别中都起着作用。