Patterns of language variation on the level of the community and of individual speakers are central to the study of variationist sociolinguistics. These patterns are also important in the study of language contact and change in that they can shed light on the factors that drive the outcomes of contact. Embedded in the fields of historical sociolinguistics and heritage linguistics, the current chapter investigates the patterning of variation, particularly intra- and interindividual variation, in the speech of Swiss heritage speakers in North America. The investigation is based on recordings made by Brian Lewis in the 1960s of selected heritage speakers from New Glarus in Wisconsin, who were born in the late nineteenth and early twentieth centuries. The focus on intra-individual and inter-individual variation of the heritage speakers allows us to shed light on the development of a Swiss heritage dialect, and particularly on processes like language maintenance and shift and possible dialect levelling in the diaspora. This chapter provides socio-historical background information on the settlement and dialect/language contact scenarios of the original Glarner migrants. Thereafter, based on the Lewis recordings, intra-speaker and inter-speaker variation related to lexical, phonological and morphological variables of eleven heritage speakers will be closely examined. To explain the intra- and inter-individual variation in the speaker, the homeland dialect, the settlement history, available schooling, contact scenarios as well as the data collection method are being considered. All of these aspects are relevant in order to better understand patterns of variation in the study of heritage language/dialect development in the past.