In the last chapter, sound-change was investigated, and it was observed that change was the result of the complex interaction of a number of different mechanisms. In the following chapter, complex interaction will be observed with regard to lexicological change.
At first sight, the lexicon of a language seems a very simple category; it is to do with words, and for many lay people the history of a language is a history of individual words: their etymology, their meaning and their changing use. However, such a fragmented notion of linguistic historiography cannot be immediately defended against the charge of atomism and thus triviality. It is important, therefore, to establish a general theory of lexicology before proceeding to the particular concern of this chapter, which is to demonstrate how lexical change is bound up with intra- and extralinguistic developments elsewhere within the linguistic and social system.
Lexicology is the study of words and their structural relations, but it is worth noting that the concept 'word' is notoriously hard to define, and that the relationship between word and meaning raises a number of quite complex issues. Before discussing the diachronic development of words, it is therefore worth establishing some basic notions which will be useful in later discussion. A useful formal definition of the concept 'word' might be as follows: a grammatical unit which is marked within the clause by positional mobility, uninterruptability and internal stability (Lyons 1968:202-204). Thus in the following sentence
(1) The papers reported the speech widely on their front pages there are no fewer than fourteen morphemes, or minimal units of grammatical analysis, separated by a hyphen (-) in (1a) below:
However, these morphemes cannot be placed in any order to produce acceptable English sentences; some permutations are acceptable, such as