[gumby]

> More people speak English than Mandarin and that language base represents a dramatically larger economy than Mandarin does.

Oh I agree but I was jocularly speculating on multiple constraints, to whit English is unacceptable as it would imply something favourable about those damned splittists; Spanish would not be acceptable because it would elevate one European country's language above others (though wasn't that the de facto story about English before Brexit?) etc etc.

In a different comment I argued for English because is not the selected language of any EU country.

Hmm, German might be a good choice as it is the EU language of three nations, so has a "majority vote" :-)