He's probably proficient in written English. Speaking it is a totally different skill.
“He’s probably proficient in written English.....”
I hope they popped the doors on the back for more than a quick looksee.....no English my a#$......
If you are aware enough to be able to read English words and understand what they mean then you should be able to muster more of a defense than just, "I don't know how to speak your language."
Mandarin Chinese falls in that category too. Speaking is easy. Reading/writing the pictographs is a major undertaking. Arabic is fairly easy to read, but requires a different inflection when addressing male/female persons.
English is so easy..."We eat what we can and what we can't we can."