Gestalt Contours, Polarity and Construction-specific Phonology in Gaahmg

In this paper, I provide a new type of evidence for sub-tonal features (Yip 1980, 2002, Bao 1999) from tonal morphology in the Eastern Sudanic language Gaahmg, based on the detailed gram- mar of Stirtz (2011): Gestalt contour formation where specific morphological categories change the underlying tone of a base word to a falling contour, but with different absolute tone values (High-Mid, Mid-Low, and High-Low) depending on the input tone. I show that the three morphophonological different global contours in Gaahmg can be captured succinctly via feature affixation using the tone geometry proposed by Snider (1990, 1998, 1999, Register Tier Theory), and that this analysis receives independent support by other general patterns in the morphophonology of the language: a pervasive sub-tonal assimilation (lowering) process, tone polarity, and minor tonal alternations triggered by specific morphological constructions. Thus, in line with recent work by McPherson (2016) and Meyase (2021), the paper undermines a major objection against tonal feature geometries, the claim that subanalyses of tone features lack broad support in language-specific tonal grammars (Hyman 2010, Clements et al. 2011). By developing a virtually complete formal tone-affixation analysis of Gaahmg’s complex tonal morphology in the framework of Autosegmental Colored Containment Theory (Trommer 2015, 2022, Zaleska 2020, Paschen 2021), the paper also provides additional evidence for the viability of this formalism in the context of the Generalized Nonlinear Affixation (GNA) program to reduce all productive non-concatenative morphology to concatenative affixation of defective partial phonological representations (Bermúdez-Otero 2012).