No matter what language is used, each national language. To keep in touch with others who are different languages, different cultures, everyone will need to use English as the primary address.
We each take what language is the national language. To interact with people of different languages and cultures of all people need to use English as the primary anyway.
No matter what language is the national language, each use. When to contact with other different languages in different cultures all need to use English as the main course.