So far, English is also the preferred language of air traffic control in many countries and is used widely in sea travel communication.
Another factor has something to do with information exchange around the world.
As we all know, a great deal of academic discourse around the world takes place in English.
It is often a lingua franca of conferences, for example,
and many journal articles in fields as diverse as astronomy, trial psychology and geology have English as a kind of default language.
The last factor I cite here concerns popular culture.
In the western world, at least English is a dominating language in popular culture.
Pop music in English can be heard on many radios, thus many people who are not English speakers can sing words from their favorite English medium songs.
And many people who are regular cinema-goers or TV viewers can frequently hear English in subtitled films coming out of the USA.
Now, to sum up, in today's lecture, we have reviewed some of the reasons or factors that lie behind the popular use of English as the No. 1 world language.
Before we finish, I would like to leave a few questions for you to think about. Is the status of English as the No. 1 world language assured in the future?
Will it split into varieties that become less mutually intelligible? Or will some other language or languages take the place of English as world language in future?
These questions are not easy to answer, I know. But they are definitely worth pondering over after the lecture.
Ok, this brings to the end of today's lecture. Thank you for your attention.