Opacity from constituency

Structural opacity often has derivation histories as deep as the number of structural tiers. This is implicit since the days of Lexical Phonology in the 1980s. However, with the advent of Optimality Theory (OT), the relationship between structural depth and opacity has become obscured due to the output-orientation of OT. This paper uses Mandarin third tone sandhi as a case study of structural opacity to develop, within OT, the Inter-tier Correspondence Theory (ICT) where structural configurations are taken into account by allowing for nonterminal nodes to reconstruct information of subordinate nodes. Since structures are built by GEN and selected by EVAL, information at the terminal nodes must come directly from the input string; information at non-terminal nodes would be derived by inter-tier correspondences. This asymmetry of terminal and non-terminal nodes allows ICT to marry the insights of both the Containment Approach and the Correspondence Approach to Optimality Theory. ICT further predicts that mere adjacency does not result in markedness, and consequently does not trigger alternation. Rather, it is to the constituency of units that markedness constraints apply. This is why derivation histories are rarely deeper than there are structural tiers.