In nonderived environment blocking (NDEB), a phonological process applies across morpheme boundaries or morpheme-internally when fed by another phonological process but is otherwise blocked. I present a theory of NDEB that attributes blocking to an interaction between morpheme structure constraints (which constrain possible underlying representations in the lexicon) and the usual phonological mapping from underlying to surface forms. The theory has some unusual aspects that make it conceptually suspicious, but I will argue that it receives empirical support. Using several case studies, I discuss three puzzles for theories of NDEB previously proposed in the literature, including the Strict Cycle Condition (Mascarό 1976), Kiparsky’s (1993) theory of underspecification, Sequential Faithfulness (Burzio 2000), Colored Containment (Van Oostendorp 2007), and Optimal Interleaving with Candidate Chains (Wolf 2008). I show that none of those theories can deal with all three puzzles and that the proposed theory with morpheme structure constraints succeeds. This result supports a dual-component architecture of phonology (as in Chomsky and Halle 1968) over architectures that eliminate language-specific morpheme structure constraints (i.e., the principle of Richness of the Base in Optimality Theory).

This squib proposes to extend the traditional taxonomy of pairwise process interactions (which contains “feeding,” “bleeding,” “counterfeeding,” and “counterbleeding”) to include the classes “shifting” and “countershifting.” A process “shifts” another if it does not feed or bleed it but rather causes it to apply in a different way. “Countershifting” is the opaque counterfactual inverse of shifting, and it fills a terminological gap identified by Kiparsky (2015) . The class of countershifting interactions is claimed to be theoretically significant: Harmonic Serialism is able to apply the opaque process in countershifting interactions but generally not in counterfeeding or counterbleeding.

We develop an evaluation metric for Optimality Theory that allows a learner to induce a lexicon and a phonological grammar from unanalyzed surface forms. We wish to model aspects of knowledge such as the English-speaking child’s knowledge that the aspiration of the first segment of k h æt is predictable and the French-speaking child’s knowledge that the final l of table ‘table’ is optional and can be deleted while that of parle ‘speak’ cannot. We show that the learner we present succeeds in obtaining this kind of knowledge and is better equipped to do so than other existing learners in the literature.