These are all blended languages which originated in the needs for traders to communicate with natives across broad stretches of territory which might have tens of basic languages and hundreds of dialects.

Over the course of time some creoles like Swahili and Creole developed into real native languages with real literatures, but in origin they are bastard blends that take a foreign vocabulary and layer it over a native grammar.

Which oddly enough is a pretty precise description of English. We have a largely French vocabulary layered over a Anglo-Saxon grammar. English is what happens when French overlords need to communicate with Saxon subjects.

The global dominance of English is pretty much the result of it being Swahili with better guns. Both are flexible languages whose origin are in cross-language and regional communication.

India has many official languages depending on which State you are in. But all official documents are also published in English which is the only common language across the country. You can be a highly educated Indian, an elected congressman and not speak a word of Hindi or for that matter Urdu. Maybe your native tongue is Gujarati and you went to school and university of a Gujarati speaking campus. Well there is a 100% chance that you are fluent in English and that when you meet at an academic seminar you will be communicating in English.

Richard Feynman had a touching story that bears on this. In "Surely You're Joking" he recounts being invited to deliver a lecture to the Brazilian Academy of Sciences. So he taught himself Portugese and developed a text for delivery. Only to find out that the language of record for the Academy was English. Not being willing to try to reverse translate his prepared text he apologized and delivered it in Portugese anyway. And the crowd went wild (or as wild as physicists go).