The acquisition of language can provide a paradigm for the entireproblem of the relation between learning and development. Languagearises initially as a means of communication between the child and thepeople in his el).vironment. Only subsequently, upon conversion tointernal speech, does it come to organize the child's thought, that is,become an internal mental function.
I wonder if speakers of multiple languages also experience the shift from using language primarily for communication with others to using it as a way of organizing their own thoughts, to the same extent as proposed by this theory.