I have found in recent years more and more companies I call on the phone, they can certainly speak English..... but are really lacking in understanding English and anything outside of the parrot English they have learnt <deleted> them.
Thats when I switch to speaking Thai.... they then understand what Iam asking.
Same happens in my work, my dept has 30 employees, all speak fluent English.... maybe 5 of them understand English which then means the daily morning meeting whilst conducted in English resorts to Thai to get the answers needed.