In the contentious and overcrowded world of English language studies, Nicholas Ostler stands out as an original analyst of a subject that usually generates more heat than light. Ostler's Empires of the Word (2005) was a critically acclaimed history of the world's languages based on his deep knowledge of linguistic theory and a familiarity with around 26 languages.

In his new book, The Last Lingua Franca (Allen Lane), he brings a wide-ranging linguistic perspective to bear on the role and future of global English. His provocative conclusion – that English is likely to go the way of Persian, Sanskrit and Latin and, over many hundreds of years, inevitably die out – will bring hope to the French and dismay to many American linguistic patriots.

Ostler is the chairman of the Foundation for Endangered Languages, a non-profit organisation that exists to support, enable and assist the documentation, protection and promotion of endangered languages. He lives in Bath.

Can you express the central theme of your book in a nutshell?

English is on an up at the moment, an up that is probably unprecedented in world history. But world history is full of languages that have dominated for a time, yet there aren't too many of them around now. So the essential idea is to see what happened to them and see if this could possibly be relevant to the situation of English, which is the world's lingua franca today.

Surely the historical circumstances that led to the decline of a language such as Persian are very different from the circumstances in which English finds itself today?

Well, inevitably they are different in that Persian only dominated western Asia and it was disempowered by the invasion of aliens, people coming from effectively another planet: the British in India on one hand, the Russians in central Asia on the other. In the history of languages, it usually takes centuries for the inevitable to come about. It probably took 700 years after Persian no longer had any obvious military or cultural means of support for it to be discredited. In the case of a language such as Latin, it took a millennium. So these things do take a long time, but there's no reason to believe that English is going to be the exception to the sort of trends one can discern.

But global capitalism, global media, global politics – isn't that a lot to discount if English will ultimately disappear?

Yes, but this sort of thing has happened in the past. I mean, do you have an explanation for why Latin wasn't given a massive buck-up by the invention of the printing press? It did get an immediate fillip, because to start with the literate public predominantly read Latin. But the trend towards vernacular literacy tended to overwhelm Latin. At the moment, English-speaking groups are very much in their ascendancy, but there is only one way to go from an ascendancy.

How will new technologies – the sort of things that allow instant translation between languages – shape the future?

It's been the received wisdom in language technology that machine translation isn't good enough. But all that's preventing it from being good enough is just a problem of scale. The way that machine translation is now being pushed forward simply involves being able to process more and more data in order to find the significant patterns. The power and cheapness of computers is increasing all the time. There's no way that the little problem of incompatibility between languages is going to stand in the way of it for long.

And because it's being done in a data-based way, the techniques which will solve the problem will solve it for all languages, not just the big important ones. So even remote Aboriginal groups will benefit – maybe a generation later, maybe sooner. And when that happens, people will be able to fulfil themselves through their own language, which is what they always wanted to do anyway.

Conventional wisdom used to be that new forms of English – Jamaican patois or Singlish [English-based creole spoken and written colloquially in Singapore] – would become mutually unintelligible. But that hasn't happened yet.

Well, it's happening gradually. But I want to draw a distinction between a language which is spread through nurture, a mother tongue, and a language that is spread through recruitment, which is a lingua franca. A lingua franca is a language that you consciously learn because you need to, because you want to. A mother tongue is a language that you learn because you can't help it. The reason English is spreading around the world at the moment is because of its utility as a lingua franca. Globish – a simplified version of English that's used around the world – will be there as long as it is needed, but since it's not being picked up as a mother tongue, it's not typically being spoken by people to their children. It is not getting effectively to first base, the most crucial first base for long-term survival of a language.

You run the Foundation for Endangered Languages. What does that do?

Half the world's languages have fewer than 10,000 speakers and these seem to be losing the speakers they have. The point of the foundation is to raise this as a matter of concern and to bring people who are concerned with these languages together, so they can learn from each other.