USA Today describes research by Jeffrey Grogger of the U. of Chicago regarding the relationship between study participants’ speech patterns as perceived by others and their income. Grogger’s study abstract reads as follows:
Speech patterns differ substantially between whites and African Americans. I collect and analyze data on speech patterns to understand the role they may play in explaining racial wage differences. Among blacks, speech patterns are highly correlated with measures of skill such as schooling and ASVAB scores. They are also highly correlated with the wages of young workers. Black speakers whose voices were distinctly identified as black by anonymous listeners earn about 10 percent less than whites with similar observable skills. Indistinctly identified blacks earn about 2 percent less than comparable whites.
The study can be viewed here (PDF).