Two distinct but related studies are reported, both investigating linguistically- and culturally-based communication problems between service providers and service seekers in Australia. The first examined language problems occurring in naturalistic situations involving a public servant and a client within three public agencies, the departments of taxation, immigration/ethnic affairs, and social security. Data were gathered ethnographically, through non-participant observation supported by note-taking and, where appropriate and permitted, by recording and interview. Analysis revealed distinct communication error patterns: sound-related linguistic lacunas; grammar-related linguistic lacunas; meaning-related linguistic lacunas; communication-related cultural lacunas; situation-related cultural lacunas; and identity-related cultural lacunas. Explanations and examples are offered for each category. A second study examined service-type interactions occurring for non-English-speaking-background (NESB) students at Edith Cowan University (Australia), reported in less detail but indicating contrasts in the two communication situations, particularly in the use of communication strategies by both NESB students and instructors. (MSE)