The research in this thesis examines the influence that both geometric and extrageometric
factors have on children's spatial language production. Over the years it has widely
been assumed that spatial prepositions identif' where objects are in the world (geometric factors)
and that this is reflected in the semantic representations of these words. More recently,
researchers investigating the lexical semantics of spatial prepositions have begun to question this
assumption by demonstrating that what objects are and how they are interacting can also affect
the way we describe where they are in the world (extra-geometric factors). Following on from
research conducted with adults that has demonstrated the importance of both of these factors on
spatial language, the main aim of this thesis was to ascertain for the first time whether these
factors also influenced children's spatial language production, and if so, when they became
important in children's development of spatial expressions. Additionally, due to the paucity of
research investigating the production of spatial terms, the Experiments reported in this theis set
out to redress the balance. The research in this thesis demonstrated for the first time that both
geometric and extra geometric factors influence the production of children's spatial expressions
from an early age. In doing so, however, the Experiments reported here were not necessarily
revealing as to the nature of the semantic representation of spatial terms, rather they highlighted
a different issue; how people make distinctions during a verbal interaction. Evidence is presented
that suggests a level of agreement between people regarding the nonconventional use of words.
In order to distinguish between functional and non-functional situations, both adults and children
used different types of spatial terms to locate an object even when they had a limited number of
words in their lexicon. An approach to the whole process of prepositional production is
suggested rather than concentrating on what is represented in an individual's lexicon