The concept of "Ethnolinguistic Vitality" (EV) has received variable acceptance and support since its introduction by Giles, Bourhis, and Taylor. It has especially proven to be a valuable heuristic in studies of language maintenance and shift. However, the reliability and validity of the instruments used to investigate EV, especially questionnaires used to test subjective vitality, have proven to be more problematic. This position paper introduces some of the issues that have been considered as difficult in the conceptualisation, investigation and application of EV and will suggest possible areas for further development. Drawing on a study of language attitudes, shift and the EV of the Greek-Orthodox community in Istanbul, this paper argues that there is much to recommend the tripartite conceptualisation of the EV framework in assessing both subjective and objective vitality via quantitative and qualitative methods. It further argues that studies of EV can be enriched by the use of ethnographic/observational approaches and discourse analytic frameworks, particularly when investigating hybridity. The adoption of both etic and emic approaches facilitates a more detailed engagement with key constructs. The latter will benefit the study of EV and potentially facilitate a rapprochement between researchers from different disciplines. (Contains 3 tables and 1 figure.)