本文主張純粹的共時音韻可能是個迷思。脫軌的現行音韻現象或釩O留了早期音韻的遺跡。三個閩南秘密語、潮陽方言擬聲字重疊和大同方言嵌l詞都見證了從歷時的角度解釋脫軌的共時音韻現象的可行性。

This paper argues that the concept of ζpure synchronic phonology' which possibly emerges as a result of the over-application of the learnability viewpoint to the study of language can be a myth. Existent phonological patterns which plague a unified synchronic analysis may actually reflect remnants of an earlier phonology. A wide range of dialect materials from three Southern Min secret languages， Chaoyang onomatopoeia reduplication， to Datong l-separated words all reveal the feasibility of tackling aberrant synchronic sound patterns from a diachronic perspectIve.