It is well documented that the phonetic realization of a sociolinguistic variable can systematically differ according to the social attributes of a speaker, such as their age, class or ethnicity. What is less understood is the degree to which listeners routinely exploit this systematicity in order to make social judgments about speakers. This study uses speech synthesis to examine whether subtle changes to the phonetic realization of sociolinguistic variables in a sentence can alter the perceived age and social class of a speaker.