本文從音韻學的觀點來分析平遙方言的連讀變調現象。平遙方言連讀變調有 兩大特點：（一）在二字組部份，平遙方言連讀變調深受詞法關係（grammatical relation）影響。（二）在三字組部份，平遙方言連讀變調仍受詞法關係影響， 只是詞法關係和變調規則時有不搭配的狀況；此外，三字組連讀變調方向和 構詞句法結構（morpho-syntactic structure）關聯不大，而主要受到詞法關係規 範。本文以優選理論（Optimality Theory）來分析平遙方言的連讀變調。在二 字組部份，本文提出兩組並存音韻理論（co-phonology）來處理不同詞法關係 的連讀變調。在三字組部份，本文指出，造成詞法關係和變調規則不搭配的 主要原因，是為了避免變調範疇已不受構詞句法結構規範的詞組又同時對應 到不同的並存音韻理論。

This paper investigates tone sandhi phenomena in Pingyao, a Jin dialect spoken in Shanxi province in China. Pingyao tone sandhi is special in that tone sandhi in bi-syllabic strings is construction sensitive, but tone sandhi in tri-syllabic strings is not fully conditioned by construction types. Based on Optimality Theory (OT), this paper proposes analyses for bi-tonal and tri-tonal sandhi in Pingyao. We show that while bi-tonal sandhi can be accounted for by assuming that there are different grammars associated with different construction types, the lack of construction sensitivity in certain tri-syllabic strings suggests that the association between construction types and phonological grammars can be sacrificed to comply with a higher demand. In Pingyao, the higher demand is to avoid having a tri-tonal string with marked tone sandhi domain from being associated with conflicting grammars.