Perceptual motivation for rhotics as a class

•Tested perception of three rhotics /r ɻ ʀ/, against three stops /dj ɖ ɟ/, three nasals /nj ɳ ɲ/, three fricatives /z̪ ʐ ʑ/, and three laterals /ɫ lj ɭ/.•Performed AX discrimination task and used D-primes to calculate perceptual maps with multidimensional scaling.•Revealed low D-prime for rhotic-rhotic comparisons, small perceptual space for rhotics, and distinct grouping in the perceptual space for each of the natural classes.•Suggests acoustic-perceptual similarity between rhotics which may contribute to class membership.•May explain typological tendency to have small rhotic inventories. Finding phonetic correlates of rhotics as a natural class has been elusive, leading to the suggestion that any class-based relationship between different rhotic categories is purely phonological in nature. This paper examines native English speakers’ perception of three different non-native rhotics (i.e., /r ɻ ʀ/) compared to non-native sounds from four other manners of articulation (stops, nasals, fricatives, and laterals). The results revealed that speakers cannot reliably discriminate between the rhotics examined here and that the perceptual distance between members of the class of rhotics is smaller than the other tested classes, aside from the comparison with laterals. The current results suggest that there is an acoustic-perceptual correlate to rhotics as a natural class and that their perception explains the relative rarity of large rhotic inventories cross-linguistically. The comparison with laterals also suggests why rhotics are often paired with laterals in inventories with two or more liquids.