本文以優選理論（Optimality Theory）探討成都話中涉及特殊變調的四種重疊型式（包含AA型式、AAB型式、ABB型式、以及 AABB型式），並針對其重疊部分（reduplicant）之大小、位置、以及重疊型式之連讀變調現象提出分析。本文指出，重疊部分的大小差異主要是受到不同對整（alignment constraint）制約的影響；而重疊部分的位置基本上出現在詞基之後，AABB型式的例外情形乃是受到要求維持輸入音段先後次序的線性制約（linearity constraint）所影響。最後，在特殊變調方面，本文指出，這四類重疊型式之變調現象看似不同，卻都內含一個浮游聲調（floating tone），且該聲調均出現在重疊部分之左側，造成特殊的變調現象。

This paper examines four reduplication patterns in Chengdu that involve special tone sandhi (i.e. AA, AAB, ABB and AABB) and proposes an Optimality Theoretic (OT) analysis to account for the reduplicant size, the reduplicant placement, and tone sandhi of these patterns. For reduplicant size, the monosyllabic reduplicant size in AA, AAB, and ABB and the disyllabic size in AABB are shown to be governed by different alignment constraints that contribute to the variant reduplicant sizes. For reduplicant placements, it is shown that though the reduplicant in AABB appears to be infixal, it is actually a suffix (just as the other patterns), whose movement into the base is forced by a linearity constraint that requires the input segmental sequence to be preserved in the output. Finally, for tone sandhi, it is shown that the special tonal alternations in the four reduplication patterns are the combinational effect of general tone sandhi and a floating high tone, which usually docks on the left edge of the reduplicant.