This paper proposes that closed syllable laxing and open syllable tensing of non-low vowels are motivated by conflicting strategies of contrast enhancement in vowel–consonant sequences. Laxing enhances the distinctiveness of consonant contrasts by allowing for more distinct VC formant transitions, in particular in sequences involving a non-low vowel followed by an oral labial/coronal/velar consonant (e.g. [p t k]). Tensing enhances the distinctiveness of vowel contrasts by providing more distinct formant realisations for vowels. Linguistic variation results from different ways of resolving the tension between maximising vowel dispersion and maximising consonant dispersion. Laxing typically applies before coda consonants as a way to compensate for the absence of good perceptual cues to place of articulation. The hypothesis that laxing enhances the distinctiveness of postvocalic place contrasts is supported by a study of mid-vowel laxing in French, which corroborates the general claim that perceptual contrast plays a role in shaping phonotactic restrictions.

中文翻译：

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对比度增强作为闭音节松弛和开音节紧张的动机

本文提出，非低元音的闭音节松弛和开音节紧张是由元音-辅音序列中对比度增强的冲突策略引起的。Laxing 通过允许更明显的 VC 共振峰转换来增强辅音对比的独特性，特别是在涉及非低元音后跟口唇/冠状/软颚辅音的序列中（例如 [ptk]）。时态通过为元音提供更明显的共振峰实现来增强元音对比的独特性。语言变异源于解决最大化元音离散度和最大化辅音离散度之间的紧张关系的不同方法。松弛通常在尾辅音之前应用，作为弥补发音位置缺乏良好感知线索的一种方式。