The language intervention model developed and evaluated at the Center on Everyday Child Language Learning (CECLL) is described. The model includes 4 components: interest-based child learning opportunities, the everyday family and community activities that are sources of interest-based child learning, the methods for increasing child participation in the everyday learning activities, and the use of responsive teaching for promoting child communication and language learning while children are engaged in the activities. Results from the evaluation of the relationship between fidelity of practitioners' use of an evidence-based coaching practice and the fidelity of parents' use of the CECLL intervention practices are presented. Implications for considering factors that influence the use of the CECLL intervention practices with fidelity are described.