In forming an impression of a speaker, listeners are attentive to the frequency of nonstandard language features, using it to calibrate their judgments. We show that the ability to track and socially evaluate nonstandard variant frequency is subject to individual differences. Listeners judged an aspiring newscaster on the standardness of her speech in a series of read-aloud passages that had been manipulated for proportional frequency of a nonstandard pronunciation. Judgments of conditions at the poles of the frequency continuum were predicted by listener sociodemographic factors. For conditions in the middle of the frequency continuum, listener judgments were predicted by Broader Autism Phenotype Questionnaire scores for communication skills. Language attitudes may therefore be affected by both social and cognitive listener attributes, where cognitive attributes are most relevant for ambiguous inputs.