An investigation into the effect of the Center for Improving the Readiness of Children for Learning and Education (CIRCLE) Preschool Early Language and Literacy Training professional development intervention coupled with 4 combinations of mentoring and electronic or written feedback on teachers' promotion of at-risk children's development of early language and emergent literacy skills, based on samples of 262 early childhood teachers placed in one of 4 variations of the CIRCLE intervention or in a control group, and 1,786 preschool students