World map of linguistic families / Wikimedia Commons
As a linguist I dread the question, “what do you do?”, because when I answer “I’m a linguist” the inevitable follow-up question is: “How many languages do you speak?” That, of course, is not the point. While learning languages is a wonderful thing to do, academic linguistics is the scientific study of language.
What I do in my work is to try to understand how and why languages are the way they are. Why are there so many in some places and so few in others? How did languages develop so many different ways of fulfilling the same kinds of communicative tasks? What is uniquely human about language, and how do the human mind and language shape each other? This is something of a new direction in linguistics. The old-school study of language history was more concerned with language for its own sake: understanding the structure of languages and reconstructing their genealogical relationships.
One of the exciting things happening in linguistics today is that linguists are increasingly connecting with the field of evolutionary biology. Evolutionary biologists ask very similar questions about species to those me and my colleagues want to ask about languages: why they are distributed in a certain way, for example, or looking for explanations for differences and similarities between them.
These similarities in outlook allow us to apply all the modern tools of computational evolutionary biology to linguistic questions, giving us new insights into fundamental questions about the processes of language change, and through that into the nature of language in general.
I recently co-authored a new paper with a set of interdisciplinary colleagues. We use methods adapted from evolutionary biology to investigate how a large group of languages had changed over thousands of years.
We chose to concentrate on the Austronesian language family (a huge family of languages mostly distributed along a broad arc from Taiwan to Easter Island) because quite a lot is known about how it spread. With a decent model of the history of a language family it becomes possible to uncover the processes of change within these languages. This is the same basic logic as when Gregor Mendel inferred the principles of heredity by observing how the patterns of variation in the forms of plants were governed by their ancestry. When we understand how the building blocks of language work, we will be further along the path to understanding the human mind.
Map of the Austronesian language family. Vrata / Wikimedia Commons, CC BY-SA
Languages are a lot more than just a bundle of words. They also include all the principles for combining those words into meaningful utterances: grammar. And, like words, grammar also changes over time. We wanted to discover whether grammar evolves in the same way as words.
The lexicons of a languages (the set of words each language has) change in two ways over historical time: the sound systems of individual languages change – meaning that their words sound different – and words are replaced by other words through processes including meaning change and borrowing from other languages. Grammars change in similar ways. Gradually, as rules morph into new rules (for example, ways of expression become acceptable which in previous generations were unacceptable – think of the who/whom distinction, which has nearly disappeared from natural speech), and in big jumps, as languages acquire whole new structures through processes like reanalysis or borrowing.