Dissertation
A Lexical and Phonological Reconstruction of Highland East Cushitic, including a Comparative East Cushitic Database
On the 9th of July, Ahmed Sosal successfully defended a doctoral thesis. Leiden University Centre for Linguistics congratulates Ahmed on this achievement!
- Author
- Ahmed Sosal
- Date
- 09 July 2026
- Links
- Leiden University Repository
The Highland East Cushitic (HEC) languages, including Burji, Hadiyya, Kambaata, Sidaama, and Gedeo, are spoken by more than seven million people in southern Ethiopia. Although their historical relatedness has long been recognized, Proto-Highland East Cushitic (PHEC) and Proto-Northern Highland East Cushitic have not previously been reconstructed in a comprehensive and systematic way. This dissertation addresses that gap.
Drawing on a comparative database of over 8,500 lexical entries from 23 East Cushitic languages, the study reconstructs major aspects of the PHEC sound system, lexicon (356 PHEC and 375 PNHEC reconstructions), and selected morphological items, and traces how the two proto-languages diversified into distinct but related modern languages. Among the main findings are the systematic glottalization of obstruent consonants, metathesis resolving impermissible consonant sequences, and evidence of sustained contact with neighboring Oromo and Omotic languages that has shaped HEC phonology in subtle but traceable ways.
The dissertation further reconstructs shared morphological patterns, including verbal derivation, case marking, and plural formation, and examines alternations at morpheme boundaries. On the basis of combined phonological and morphological innovations, it refines the internal subgrouping of HEC, supporting Burji as the earliest split and grouping the remaining languages within a Northern HEC branch.
The accompanying lexical database is made openly available and links source forms, cognate sets, and reconstructions to support transparency and reproducibility in comparative African linguistics.