Tier

音层

A term in hierarchical models of phonology for a level of phonological representation. For example, in autosegmental phonology, parallel tiers of phonological segments are proposed, each tier consisting of a string of segments, and representing a sequence of articulatory gestures or acoustic transitions. In a tone language, for instance, tones are represented on one tier, which specifies features of tone and nothing else; other (non-tonal) features are represented on a separate tier. Features cannot appear on more than one tier, and thus tiers can be defined by the features found in them, as in the case of the phonemic tier, the skeletal tier and the X-tier. The number of tiers varies between models. In particle phonology, for example, there are five: syllabic, nucleus, timing, root and particle tiers. Terminology varies greatly among different models, as in the case of the tier handling information about articulation, which has been called a ‘featural’, ‘gestural’, ‘melodic’, ‘segmental’ and ‘articulatory’ tier.

音系学的各种层级模型用来指一个音系表征层面。例如自主音段音系学建立两个平行的音系音段层，每个音层为若干音段组成的语符列并代表一些发音音姿或声学音渡组成的序列。例如，对于声调语言，声调在一个音层上表征，这个音层只标明声调特征不标明其他特征；其他（非声调）特征在另一个音层上表征。特征不能在一个以上的音层上出现，因此音层可以用出现在其上的特征来定义，例如音位层、骨架层、X-音层。不同的模型音层的数目不同。例如在粒子音系学中有五个音层：音节层、核心层、时标层、根层、粒子层。不同的模型所用的术语也很不一致，例如处理发音信息的音层有“特征层”、“音姿层”、“节律层”、“音段层”、“发音层”等各种名称。