Parental support is critical for young children's language and literacy development. It is important that teachers are aware of this parental role. Particularly in the case of lower-educated parents, teachers can improve their education when they engage parents in partnerships to support young children's language development. These parents are often challenged to provide a rich Home Language Environment (HLE) with opportunities for interaction and using language. However, teachers have little experience in building partnerships with lower-educated parents. We designed a series of interventions to establish partnerships between school and lower-educated parents and to encourage rich parent-child interactions. In close collaboration with teachers, principals and parents, we evaluated the application of these interventions using interviews, questionnaires and classroom observations. The results show that most teachers implemented the interventions in their classroom as intended. However, some teachers experienced problems with modelling activities to parents and stimulating parents to follow their child's initiative. Our findings also show that parents increased their participation in parent-child activities, showed more interactive behaviour with their child and were positive about their participation in the programme and its relevance. Furthermore, the school teams saw opportunities for continuing to work with the programme. Nevertheless, we also observed practical problems such as insufficient preparation of teachers for working with parents during pre-service teacher education and a lack of supportive school policy. Finally, we examine how the prototype can be better adapted to the needs and resources of teachers and lower-educated parents.