I mean, people would obviously propose English to be the world language, but its problematic since that is like telling the world that British Imperialism is somehow “okay”, which is not okay.
So we need another language.
But how could we possibly agree on one?
Do we just find the 100 rarest languages then use one of those?
Do we create a new one?
The real, most simple answer is: you wouldn’t, at least not unless we shift into a world where there are significantly less languages.
Any world government would have to contend with the reality that the world is full of multiple languages. So a number of lingua francas would be chosen as the “official languages” - either the most spoken or the most politically important (probably one and the same).
The idea to create some sort of apolical, unproblematic language just isn’t realistic. If it was, it would’ve already occurred on a mass scale. You could just as easily paint an artificial language in a negative light as you have with English: any artificial language would be taking up the place of a real, authentic language and imposing itself onto peoples who do not speak it (language imperialism of an artificial kind isn’t much better).
Besides, translators are only getting better and better and we already have a number of multi-national institutions that function fine despite the number of languages at play (e.g the EU).