Secondary glottalisation in Central Chadic (Afroasiatic)

Continued in-depth historical-comparative research into Central Chadic phonology reveals that present-day Central Chadic languages possess a number of phonemes that cannot be reconstructed for Proto-Central Chadic. Among the driving forces for their evolution were processes of ‘prosodification’, whereby articulatory features such as PAL (palatal), LAB (labial), NAS (nasal) and GLOT (glottal) disassociate from their original host segments and become ‘floating’ and thereby free to re-associate with other hosts within the word. In Chadic linguistics, such suprasegmental processes and effects are referred to as ‘prosodies’. As a result, present-day languages possess innovative palatalised, labialised, prenasalised, and glottalised consonants and approximants as much as considerably enriched vowel systems. The paper discusses diachronic scenarios according to which ‘secondary’ glottal(ised) segments emerge in addition to safely reconstructed ‘primary’ *ɓ and *ɗ. In one scenario, allophonic glottal stops end up as a floating feature (GLOT), which re-associates with another segment in the chain of phonemes resulting in glottal ‘colouring’ of the new host. In a parallel scenario, an allophonic glottal stop ends up in abutting position to another segment, with which it fuses and likewise fosters a new synchronic glottal phoneme.