If you had to remove one global language from the world, which would cause the most chaos?

Let’s make this more interesting and take English out of the equation.

Aside from English, which widely spoken language disappearing overnight would create the biggest disruption? Think trade, migration, regional politics, online spaces, science, tourism.

Would it be Spanish because of how many countries rely on it across continents? Mandarin because of economic weight? Arabic because of religion and cross regional communication? French because of its role in diplomacy?

Which one would cause the most real world chaos and why?