源於複雜性的凸顯性：捕捉天津方言二字組變調規律

Prominence from Complexity: Capturing Tianjin Ditonal Patterns

天津方言高低升降四個基本調形，兩兩組合成十六個二字組，當中有六種產生變調。變調之所以產生說法不一：一說是強行曲線原則在聲調的調形與調徵兩個不同層面運行；一說認為是調形跨音節時平化。細察之則不難發現兩說皆有待補充，而將天津方言視為通過聲調調形複雜性體現起右重（即抑揚格）節律乃最有效辦法。是故本文提出 主位調複雜性制約條件(HTC)以配合強行制約原則得出天津方言僅有的六種二字組變調。

This paper explores the six ditonal sandhi that spawn from an inventory of four tones (Low, High, Rising, and Falling) in an attempt to provide an account for why only certain ditonal combinations trigger alternation but not others. Earlier accounts have relied on Obligatory Contour Principle (OCP) applying to adjacent syllables both at the level of the full tone contour and also of the tonal features that comprise the contour. Another account has explained sandhi in terms of leveling across syllables so that excessive contours are avoided. A careful exploration reveals that neither of these approaches is adequate, nor are some of their stipulations necessary. Instead, a more viable solution might be found if we accept that Tianjin prosody is right-headed such that prosodic prominence is reflected through tone complexity. To this end, I propose the Head Tone Complexity (HTC) constraint that partners with OCP to generate the attested ditonal sandhi patterns.