This theoretical handbook draws together the theory and evidence underpinning the practical outputs of the project: the training programme and the practical handbook.

It comprises four main parts:

• The first provides a review of relevant literature on early language development and a rationale for why language development in nature may be beneficial for young children. It summarises existing literature that looks at early language development in nature.
• In Part 2, our integrated formative evaluation process and its results are reported and discussed. In the final part of this section, we bring together some key points from our examination of theory and research to support the value of early language development in nature, summarising the new learning that has been achieved through the ELaDiNa project.
• The third part sets out a generic model that has been developed from what is currently known about this field, (Part 1), what we learnt from the ElaDiNa Project and its evaluation (Part 2) and from previous experience of a pilot project conducted in Marburg, Germany that formed the initial seed from which our ElaDiNa project grew.
• In concluding this theoretical handbook in Part 4, we summarise the successes and challenges of the project, its main learning points and suggest some implications for policy, practice and further research.