Prosodic rhythm was measured for a sample of 20 African American and 20 European American speakers from North Carolina using the metric devised by Low, Grabe and Nolan (2000), which involves comparisons of the durations of vowels in adjacent syllables. In order to gain historical perspective, the same technique was applied to the ex-slave recordings described in Bailey, Maynor and Cukor-Avila (1991) and to recordings of five Southern European Americans born before the Civil War. In addition, Jamaicans, Hispanics of Mexican origin who spoke English as their L2, and Hispanics speaking Spanish served as control groups. Results showed that the North Carolina African Americans and European Americans were both quite stress-timed overall, with no significant difference between them. Spanish emerged as solidly syllable-timed, while Jamaican English and Hispanic English were intermediate. The ex-slaves were significantly less stress-timed than either younger African Americans or European Americans born before the Civil War. This finding suggests that African American English was once similar to Jamaican English in prosodic rhythm.