The syllabic liquids [ɚ] (as in “purr”) and [əɫ] (as in “pull”) have well-defined acoustic targets but are produced with a wide range of heterogenous tongue postures. This work surveys midsagittal tongue shapes from a large (N=78) number of speakers producing these sounds, to illustrate their variety, and to determine systematically how this variety can be quantified. In particular we propose that a categorization based on just two parameters––degree of tongue dorsum convexity and tip orientation––is sufficient to classify observed shapes, and superior to defining ad hoc prototypes.