English is the language of business thoughout the world.
French is the language of diplomacy.
Anyone hoping to engage in trade with another country must be able to speak English, and if they want to avoid an arse kicking, they must be able to speak French.
English does originate from German, so I guess we are all speaking modified German anyway.
Asking people to forget their first language is asking people to forget their culture. That is wrong.
Asking people to learn a new language to make going to the doctor and getting a correct diagnosis is advisable. That is right.