Grammaticalisation
So far in this book, we have taken a mainly synchronic approach to language. In other words, we have concentrated our discussion upon languages as they are now, in the early years of the twenty-first century. In particular, we have focused on Modern English. As we saw in Chapter 4, the process of language change is continuous. Historical linguists take a diachronic view of language, describing patterns of change and attempting to account for those changes. The findings of historical linguistics have implications for most areas of modern linguistics, because language change affects phonology, semantics and grammar, and can therefore inform synchronic theories about these core areas of language. In addition, as we saw in Chapter 4, the causes of language change can often be attributed to socio-linguistic forces, which entails a close link between historical linguistics and socio-linguistics. There is also a close interrelationship between historical linguistics and linguistic typology (see Chapter3), since it is largely by looking at patterns of language change and dis covering the directions that such changes follow that typologists can form a view on the directions that typological patterns are likely to follow.
Some types of language change move at a more rapid pace than others. For example, the lexicon of a language changes more rapidly than its phonology or its grammar, with new words coming into the language, old words falling out of use and existing words taking on different meanings. The sound patterns of a language change more rapidly than its grammar (compare the modern ‘Received Pronunciation’ accent of British English with its 1950s counterpart, for example). Finally, the slowest type of language change is grammatical change. For example, as we will see in section 21.3, while the English verb must was a full content verb in Old English, as attested in the Old English corpus (for example, in the epic poem Beowulf, written sometime in the eighth century), in Modern English it functions as a modal auxiliary. These two points in the history of this symbolic unit are separated by over a thousand years. As Heine et al. (1991: 244) observe, the time span involved in grammatical change depends on the kinds of grammatical elements involved.
The type of language change we focus upon in this chapter is grammaticalisation. (Some linguists prefer the term ‘grammaticisation’.) This is the process whereby lexical or content words acquire grammatical function or existing grammatical units acquire further grammatical functions. Grammaticalisation has received a great deal of attention within cognitive linguistics. This is because grammaticalisation is characterised by interwoven changes in the form and meaning of a given construction and can therefore be seen as a process that is essentially grounded in meaning. Furthermore, cognitive linguists argue that semantic change in grammaticalisation is grounded in usage events, and is therefore itself a usage-based phenomenon. There are a number of different cognitive theories of grammaticalisation, each of which focuses on the semantic basis of the process. After providing an overview of the nature of grammaticalisation (section 21.1), we discuss three of these theories below: metaphorical extension approaches (section 21.2); Invited Inferencing Theory (section 21.3); and Langacker’s subjectification approach (section 21.4). Finally, we present a brief comparison of the three approaches (section 21.5).
