David Crystal has been confirmed as the opening speaker for English UK's new Academic Conference in January.

He will speak twice on January 20, our teacher-facing day, giving the opening plenary about English accents past, present and future, and tackling the subject of language and the internet in an elective session later.

The programme is primarily aimed at teachers, whereas the opening day, January 19, is designed to meet the needs of academic managers. The conference is being held in London, and we welcome people booking for both or either days.

In advance of the conference, we asked Professor Crystal - who is a worldwide expert on the English language, author of over a hundred books, and honorary professor of linguistics at the University of Wales – a few questions about current trends in English, and in particular around the development of the language as a lingua franca.

He does not think the internet has played a role in the development of ELF as a genre, because it has only existed for around twenty years. "It takes much longer - several decades - for a factor such as a new technology to make a permanent impact in relation to grammar, punctuation and spelling, which are the primary factors identifying a genre of written English. Vocabulary change can be quicker.

"If there are common factors identifying ELF as a genre, it will take some time for these to establish themselves in a predictable way, and the internet doubtless will play a major role in enabling that to happen. But that is for the future."

What the internet has done is to publicise the issue of ELF, says Professor Crystal, with the online availability of the VOICE corpus and other materials providing some basis for the claims being made.

"However, the identity of ELF as a universally used 'variety' of English is still very much an open question. It isn't yet possible to say with confidence which features have general validity, for all second-language users, though there are a number of interesting hypotheses around - such as the replacement of uncountable by countable nouns: researches, informations, furnitures - that sort of thing. We await a reliable descriptive account of the genre, though I'm impressed by the ongoing research that is moving us in that direction."

It is not yet possible to say which factors are the main drivers of the changes, he says: beyond business, travel and entertainment there is international educational and political contact and social media. "And the role of the classroom in introducing and promoting ELF features is a little-studied domain. How these factors interact is unknown."

What effect is this having on the way that people speak English?

"The potential impact on spoken English is minimal at the moment, as the internet is still predominantly a graphic medium. This is slowly changing, as it becomes more audio-based, and the increased exposure to other accents may well one day have an effect, as people accommodate to each other, as they do in everyday life. But that also is for the future."