Martine van der Pluijm

86 Chapter 3 experiment with this behavior and rewarded their accomplishments (Hattie & Timperley, 2007). Continuous moments of reflection contributed to teachers’ awareness of the impact of their changed behavior and their motivation to continue this behavior. Third, the collaborative process of learning together (e.g., with colleagues, parents, and researchers) contributed to teachers’ motivation to develop new behavior. Evaluations showed that teachers felt supported by this collaborative approach. After almost two years of research, several teachers opted for the next round of research because they wanted to sustain this collaborative learning. The benefits of these collaborative learning processes, characterized by reciprocity and in-depth learning, were also demonstrated in previous research into teachers’ professional development programs (e.g., Epstein, Jung, & Sheldon, 2019; Hoover-Dempsey et al., 2002; Van Veen et al., 2012). Teachers in our study needed more knowledge about the impact of the HLE on young children’s language development and about families’ HLE than expected. Teachers also required more help in supporting lower-educated parents changing their interactive behavior with their child. This is in line with previous research demonstrating the need to equip teachers with additional knowledge and abilities to support lower-educated parents (e.g., De la Rie, 2018; Lusse, 2013; Van der Pluijm, 2014). During this study, we accommodated teachers with this additional support according to their individual needs (e.g., more background information, assistance, modeling). Nevertheless, three teachers evaluated the program as less usable for their target group. Based on our findings and the recommendations of teachers and school principals, future professionalization needs some modifications. First, more theory about the importance of parental roles for child language development may contribute to the awareness of teachers. Recognizing parents as first educators of children may motivate teachers to prioritize building relationships with parents in support of young children’s language development (Sheridan et al., 2019). Attention should focus on families with the least resources (i.e., low parental education level, parental literacy skills), which negatively impact child opportunities. Coaches can stimulate teachers to investigate possibilities to improve the access of families to knowledge and resources for child education at home that can contribute to more equitable opportunities for child development (Green, 2016). Second, embedding the use of the class inventory list in a workshop with the previously mentioned theoretical perspective that positions parents as first educators of their child may motivate teachers and decrease mixed feelings about the usability of the prototype that we found in this study. Using the class inventory list can be one of the first actions for teachers to improve their understanding of the resources that are available in the home environments of their pupils. Exchanges among teachers about their parent population may further stimulate learning about their backgrounds that impact the HLE. After this start, gaining more insight