Family language policy (FLP) has been defined as "explicit and overt planning in relation to language use within the home among family members" (King, Fogle & Logan-Terry 2008, 907). Yet, language practice patterns are not static and may evolve over time between different family members, in response to changing language contact and exposure patterns (Spolsky 2008). For this paper, we draw from data collected in an ongoing five-year longitudinal study exploring the impact of exposure and input in bilingual acquisition and development in French-English bilingual children (middle to high SES families) in the Anglophone section of an international state school in France. To enter the school, children require at least near-native English proficiency, while non-French-speaking children attend French as a foreign language classes for several hours a week. The children are divided into two groups: 1) 22 children aged 5-6 and 2) 33 children aged 10-11. Four main family profiles are present in the sample: 1) children with one Francophone and one Anglophone parent; 2) children with two Francophone parents who have lived in an English-speaking environment for between two and five years before returning to France; 3) children with two Anglophone parents living in France on a long-term basis; and 4) children with two Anglophone parents, in France for between two and five years. Thus certain children have had bilingual exposure from birth whilst others started with monolingual exposure and came into contact with a second language at a later stage in their development. Parent questionnaires provide data on family background and children's language exposure from birth. Parents are also asked to self-evaluate their language skills in French and English. Individual interviews with parents provide crucial insights into family dynamics and factors which may lead to changes in language choice and interactional strategies. Semi-structured interviews with each child provide further data on participants' language biographies (Simon 2014) and current language strategies with family members. This paper aims at exploring the different factors influencing the FLPs from children's birth to the present within the different family profiles. We focus on how each member of the family (fathers, mothers and children) negotiates and contributes to the shifts in language practices. For instance, we question how language use patterns evolve and how these changes may be accounted for. Our results suggest that language choices within the home are determined by a range of factors over time. In some cases, children's language shifts shape parental language strategies following a family move from another country. Furthermore, mothers are more likely than fathers to change their language behaviour. Interestingly, parents who shift from a monolingual to a bilingual policy do not necessarily consider themselves to be proficient speakers of the second language. Sibling language use patterns may shift once one child is enrolled in formal education but our findings also reveal the potential contribution of peers and friendship networks.