I propose that the notions of segment and phoneme be enriched to allow some concurrent clustering, even in classical theories. My main application is the Khoisan language !Xóõ, where treating clicks as phonemes concurrent with phonemic accompaniments allows the inventory size to be radically reduced, so solving the problems of many unsupported contrasts. I show also how phonological processes of !Xóõ can be described more elegantly in this setting, with support from metalinguistic evidence and production-task experiments. I describe a new allophony in !Xóõ. I go on to discuss other applications, some rather speculative, of the concept of concurrent phoneme. The article also provides a comprehensive review of the segmental phonetics and phonology of !Xóõ, together with previous analyses.