At this age language is crucial, the move to primary school means different subjects being learnt, different vocabulary being used, getting used to different teachers using different styles. There is more self-organisation needed. Language, both spoken and written, become increasingly abstract. There is an expectation to put together language to form reports and stories and more problem solving and verbal reasoning skills are used. Socially interactions become more complex ,conversations become longer and more varied language including slang is used.
This can be challenging , for all at this age , but for those with language difficulties it can have a can have a significant impact resulting in poor learning outcomes, social isolation and behavioural difficulties.
