The Fate of PIE *(-)sp- in Continental Celtic and Towards a Comprehensive Classification of the Evolutions of PIE *p in Celtic

The total loss or mutation of /p/ is the quintessential feature that grants the status of Celtic language within the Indo-European family. Therefore, the evolution of this sound has been the subject of multiple studies over the last two centuries. However, there are still crucial issues to be addressed, which will be dealt with at length in the present paper. On the one hand, we will conduct a systematic and critical review of the proposed results of PIE *p in terms of the phonetic context and Celtic dialectology, thus providing a comprehensive overview of all evolutions. On the other hand, we will attempt to elucidate some obscure points of the historical phonetics of Celtic, namely the results of the sequences *#sp- and *-sp-, drawing equally on insular and continental material. Hence, not only will new light be shed on the history and relative chronology of linguistic change in Celtic, but we will also deepen our knowledge of the fragmentary Continental Celtic languages through epigraphic and literary evidence.