The topic of this study is grammatical tone (GT), which I define as a tonological operation that is not general across the phonological grammar, and is restricted to the context of a specific morpheme or construction. In typologizing grammatical tone, I frame it in terms of dominance effects (Kiparsky & Halle 1977, Kiparsky 1984), and divide GT into two types. Dominant GT systemically deletes the underlying tone of the target, while non-dominant GT does not systemically delete it. From a survey of GT, I develop a typological principle called the dominant GT asymmetry, which states that within a multi-morphemic constituent, the dominant trigger is a dependent (e.g. a modifier of affix), and the target is a lexical head or a dependent structurally closer to the lexical head. In this way, dominance is always directed ‘inward’ within morphological hierarchical structure, supporting earlier statements such as Alderete’s (2001a, 2001b) ‘Strict Base Mutation’. For any theoretical model of dominant vs. non-dominant GT, I show there are three problems that must be addressed: the origin problem (where does the grammatical tune come from), the erasure problem (why do the underlying tones of the target go unrealized), and the scope problem (what determines where the grammatical tune docks, i.e. its scope).Under this theory, the origin problem is attributed to floating tones which are part of the underlying representation of the trigger. A major claim is that there is no representational difference between dominant and non-dominant tone: both involve floating tonemes. I implement my model within Distributed Morphology (Halle & Marantz 1993), whereby triggers of dominant GT are not constructions (as in classic Cophonology Theory – Inkelas 1998), but rather individual vocabulary items (following Sande & Jenks 2017). Dominant triggers have a special cophonology which ranks a constraint enforcing dominance higher than default constraints. This dominant constraint should be understood as a special type of faithfulness: correspondence between a matrix derivation and an abstract basemap consisting of only unvalued tone bearing units, e.g. an input-output basemap //ⒽⓁ + ττ// --> \τ́τ̀\. This addresses the erasure problem. The central insight here is that dominant GT should be characterized as a special type of paradigm uniformity effect, a hypothesis referred to as dominance as transparadigmatic uniformity.To address the scope problem I develop a theory in which syntactic structure is mapped to a hierarchical morpho-phonological tree via an operation at spell-out called hierarchy exchange. Within instances of dominant GT, a mother node in the morpho-phonological tree consists of the trigger of the grammatical tune (one daughter) and the target (the other daughter). The cophonology of the trigger scopes over the entire sequence, with cophonologies applying cyclically at each node resulting in ‘layers’ of grammatical tone. A major component of this model is that hierarchy exchange preserves the inside-out derivational history of the syntactic module by referencing asymmetrical c-command. In this way, syntax/phonology interface models which appeal to c-command are essentially correct, the most relevant being McPherson (2014) and McPherson & Heath (2016). I conclude that the real legacy of c-command may not be linearization (Kayne 1994), but rather is in delimiting the scope of morphologically-triggered phonological operations.
