The Coaching Early Conversation Interaction and Language (CECIL) Project, which started in September 2020, has focused on exploring coaching-led approaches to support the effective implementation of early language interventions, especially in Private, Voluntary & Independent (PVI) settings. At the core of the CECIL approach is a way of thinking about continuing professional development (CPD) informed by the logic model (Sims and Moss, 2017) that in order to achieve the best outcomes for children, there is a need for skilled and knowledgeable practitioners which can not be achieved by training alone but requires coaching support to build motivation, confidence, knowledge and embed skills ensuring effective and sustained good practice. This document summarises the key learning from the CECIL Project, led by the Sutton Trust in collaboration with the Institute for Employment Studies (IES). It builds on the CECIL summary published in March 2022 (Barbour, 2022) which described Phase 1 of the project, by describing the activity and outcomes of Phases 2 and 3 and pulling together the key findings from the programme as a whole. [This report was supported by the Esmée Fairbairn Foundation, The Lindsell Foundation, and Shine Trust.]