2.14 Transition from interpsychological functioning to intrapsychological states is a mediational process reliant upon reflection.
2.15 Learning moves from a predominately social cognitive process to a metacognitive process supported by critical reflection and facilitating problem solving.
2.17 Internal verbalisation and verbalisation support metacognitive processes such as planning, strategy identification and application, and the monitoring and control of cognitive processes in problem solving contexts.
See other related assertions on page 26 in the book The Taxonomy of Metacognition.