AbstractPhonaesthemes are a common phenomenon, but they are generally not in paradigmatic opposition like morphemes are (Svantesson 2017: 6). Reta, however, has a phonaesthemic contrast /l/~/r/, where /r/-colouring of neutral base words signifies an increase in vulgarity, intensity, size or severity (e.g.ɓela‘bad’ vs.ɓera‘terrible’, -ool‘penis’ vs. -oor‘cock’). This paper describes this phenomenon in detail, and provides a discussion as to whether it is best classified as morphological, phonaesthemic, or otherwise. We argue that, although some of the cross-linguistic criteria for phonaesthesia exclude phonaesthemic /r/ from being classified as such, it is not straightforwardly classified as either phonological or morphological. UsingKwon & Round’s (2015)criteria for phonaesthesia and derivational morphology, we compare Reta phonaesthemic alternations to similar phenomena in other languages. We argue that such alternations differ fundamentally from both non-alternating phonaesthemes and morphology, and are best construed as a distinct cross-linguistic category.