A large number of studies have demonstrated that a linguistic unit with higher frequency and that with higher contextual predictability are realized with reduced speech signals. This effect is known in previous literature as probabilistic reduction. A few studies also demonstrate that these contextual effects may be memorized; that is, average predictability may also influence phonetic redundancy in speech signals. This study aims to investigate the extent to which probabilistic reduction effects extend to morpheme duration in Japanese. It is demonstrated that the production of a morpheme in Japanese is influenced by morpheme frequency, contextual morpheme predictability, and average morpheme predictability. These findings are interpreted to mean that speech signals are influenced by ease of lexical access or they are modified to maximize communicative ease, and the productions are accumulated in the mind of a speaker.

大量研究表明，可以通过减少语音信号来实现频率更高，上下文可预测性更高的语言单元。在以前的文献中，这种效应被称为概率降低。一些研究还表明，可以记住这些上下文影响。也就是说，平均可预测性也可能会影响语音信号中的语音冗余。这项研究旨在调查日语中概率减少作用扩展到语素持续时间的程度。结果表明，日语中语素的产生受语素频率，语境语素可预测性和平均语素可预测性的影响。