Language development in the transition from childhood to adolescence: the role of grammatical metaphor

Language development in later childhood is often characterised in terms of increasing complexity. While other linguistic theories might describe such complexity either in structural terms or in semantic terms, it is proposed in this thesis that a systemic model might explain developing complexity in terms of the relationship between the grammar and the semantics. The thesis argues that around adolescence, there is a qualitative change in this relationship, whereby in addition to the system expanding in terms of greater delicacy, there is a compounding of the system - meanings are realised not by new additions to the system but by deploying in new ways lexicogrammatical resources already in the system which have developed to realise other meanings. There is no longer a 'simplex' (congruent) relationship between the semantics and the lexicogrammar, but a 'complex' relationship, whereby in the metaphorical1 lexicogrammatical choice, there are (at least) two meanings immanent. Whereas the transition to the mother tongue is characterised by metafunctional complexity (the lexicogrammar allowing the child to mean ideationally and interpersonally at the same time), the transition to adolescence is characterised by a further level of complexity whereby the child is able to mean metaphorically as well as congruently. -- The basis for distinguishing between the congruent and the metaphorical has been described by Halliday in terms of the phylogenetic, ontogenetic and logogenetic histories of this phenomenon. Using ontogenetic and logogenetic analysis, this longitudinal case study has demonstrated that there is in fact a marked development in the child's deployment of various categories of grammatical metaphor in later childhood. The study identifies certain uses of language in early childhood which could be regarded as 'gateways' to grammatical metaphor, including various protometaphorical categories. As the child enters school, a very limited use of some types of grammatical metaphor has been observed. In later childhood, however, there is a dramatic increase in the use of most types of grammatical metaphor. If a distinction is made between a more liberal and a more conservative interpretation of grammatical metaphor, then it is possible to identify certain uses of grammatical metaphor which develop later than others and which have significant implications for learning in secondary school.