Redundancy

羡余的

A term derived from information theory and applied to the analysis of the range of features used in making linguistic contrasts. A feature is redundant if its presence is unnecessary in order to identify a linguistic unit. Features of sound (grammar, meaning) which are not considered redundant are distinctive.

原为信息论术语，现用来分析造成语言学中对立的各种特征。一个特征如果为识别一个语言单位所不必出现的，就是羡余的。不被认为是羡余的语音(语法、意义）特征是区别性特征。