19 Dec 2001,
Three major child development theorists all agree that language is linked to cognitive development, but each has a different view on its role in thought. Bruner suggested that language is essential for abstract or 'symbolic thinking' and that without language, higher level thinking could not be achieved.
Piaget believed that language developed out of cognitive development and was the tool rather than the cause. Vygotsky took the view that language and thought develop separately until the age of around two years, when they merge, allowing rational speech.