Examined the extent to which phonological performance varied as a function of test–client congruence on 3 tests of articulation containing standard English assumptions among 10 African-American children (aged 5 yrs 11 mo to 6 yrs 11 mo) who spoke 'Black English vernacular.' Results suggest that African-American children perform differently on standardized tests as a function of the linguistic norms used to score items. A failure to take the issue of dialect variation into account substantially increased the likelihood of misdiagnosing normally speaking African-American children as having articulation disorders. (PsycINFO Database Record (c) 2016 APA, all rights reserved)