[fr] Based on the data of two large scale national research projects funded to investigate the language behaviour and identity in Lithuanian communities abroad, the paper will deal with the issues of family language policy and heritage language maintenance. During both projects quantitative and qualitative methods were applied. On-line surveys (total sample 2610 respondents) have been conducted and in-depth interviews with informants face-to-face or via skype have been recorded with Lithuanian migrants living in Europe and other continents (North and South Americas, Australia). The paper analyses the family language policy and language practices in the home domain of different waves of Lithuanian migrants : 1) those emigrated in the end of 19th century and after the WWI (mainly economical emigrants), 2) after the WWII (mainly political emigrants), 3) after 1990, when Lithuania detached from the Soviet Union and re-established its Independence (mainly economical emigrants). Spolsky’s language policy model, where language policy is seen as constituted of three interrelated but independently describable components – practice, beliefs, and management – is taken as the base for the analysis. The paper explores the data of both quantitative surveys and qualitative in-depth interviews in order to find out the role of orality as an everyday practice in heritage language maintenance.