It is believed that English will become the only global language in the world. The main advantage is that global tourism will develop, whereas extinction of cultures is a huge drawback.
One language for all countries will contribute to the tourism development. People struggle to travel freely across the world, because they face language barier in some countries, where tourism is not developed as well as in Turkey. However, this problem can be solved, if all countries speak English. It is a great chance for countries with weak tourism to attract tourists. Since countries will speak in English, it will be easy to book a hotel, find interesting places or make an order in restourant. Countries can save money on building places for foreigners or hiring staff who can speak in different languages.
Regarding to the disadvantage, numerous cultures will be forgetten because of the dominant English language. Language is not only about a communication, but also about culture of nation. Since speaking foreign language leads to forgetting mother tongue, people will forget culture of their nation. For instance, in Kazakhstan, Russian language is dominant among teenagers. That is why adolescence do not know Kazakh language and forgot traditions of Kazakh language. The consequances can be terrifing, because the whole nation will disappear, because they do not have unique culture anymore. Therefore, countries that was builded on national identity may lose the freedom.
In conclusion, having one global language is beneficial for tourism development, however it puts culture and national identity of a nation in danger of dissappearing.