This sociophonetic study examines the monophthongization of /ay/ in the speech of Oprah Winfrey, the African-American host of a popular U.S. daytime talk show. We argue that both internal linguistic factors (lexical frequency), and external sociolinguistic factors (ethnicity of referee) influence the phonetic implementation of this variable. We extracted 229 tokens of /ay/ from samples of naturally-occurring speech of the speaker on the show. Tokens were identified as monophthongized by both auditory and acoustic criteria. We performed a binomial stepwise regression analysis which showed that both ethnicity of referee and lexical frequency were significant predictors of the variation in our data set, with both factors promoting monophthongization. Our results suggest that it is highly frequent words which emerge as the best candidates for the display of speaker style.