The focus group method has rapidly gained credibility among researchers in many fields, including public health researchers. The increased use of focus groups by public health researchers has underscored the demonstrable need for the capacity to apply this method of research among populations with limited abilities in or cultural resistance to conversing in Standard American English (SAE). This paper addresses the issues fundamental to the use of the focus group method among such populations. It discusses the rationale, methodology, and interpretation of focus group research among nonnative English speaking populations and the U.S.-born populations inhibited by poor education or differential linguistic patters. The paper employs research examples looking at American Indian, Mexican and Central American immigrants using several dialects of New World Spanish, low-income African Americans, and aging Appalachian coal miners. The current scarcity of linguistically and culturally competent group moderators or facilitators makes research in this area difficult, as do methodological issues including recruitment, intra-group social ranking, and outcome interpretation. It is demonstrated that valid focus group research with linguistically marginalized groups is possible, but the difficulties are many. (KFT)