Sir

I have noticed a trend among speakers at scientific conferences to speed up their oral presentations so that they can compress as much information as possible into their allocated time slots. Talking so fast can create a problem for those in the audience whose native language is not the one being used by the speaker — almost invariably English on today's stage.

For oral presentations to function as a clear mode of communication, I have some advice for speakers addressing an international audience. Bear in mind the diversity of your listeners and practise your talk on scientists whose first language is not English (and on those outside your discipline, in the case of a broader-themed conference); keep to the speed of a public-radio news broadcast; avoid cluttering your speech with unnecessary words and jargon; and do not launch into an unrelated story while presenting a text slide.

Contrary to popular belief, text slides and slide reading are not always boring, particularly for people listening to a talk in an unfamiliar language. And spare a thought for foreigners in the audience who may find jokes confusing: make sure that the humour translates!