I work with pilots and cabin crew of several nationalities who all speak English.
Their command of the language varies: the nuances and subtleties sometimes evade them, nevertheless, they are all competent English speakers.
The vast majority find that their language skills improve with use, my French, German, Dutch and Spanish all vanish if I don't use the language!
It is very easy to hang a tag on something: academics are masters of the art, those who can do those who can't teach!