I don't know how it is in other countries
when it comes to India,there are many languages,people don't know each other's language,hence English is one of the most important thing for communication.and also it is one of the most important thing which is to be known by each and every person so that he/she can easily communicate to get a job in an interview
even in government sectors and other offices only English is spoken so that every commen and individual can understand.
when two states or two Contries communicate even they speak in English
hence one does not know english then it is very hard to communicate with others