Sorry, when I said "their training" I meant -- "all their training".Not so sure about that being strange.
Remember that in the interdiction role they would Need to be able to direct an interdicted aircraft or ship. That means having the fluency to speak English Step by step in a directed manor or being able to communicate with potential allies or adversaries. This may have been a specific exorcise intended to prove that they could do that.
Training for certain scenarios with English obviously is fine and should be done, but if all of their DACT or BCM training is done with only English, that would be weird.