I had enough trouble understanding public transport signs written in my native English.
A late nineteenth century British railway company had great trouble from a literary figure of the day (and I totally forget who it was) who wrote to the company inquiring into the meaning of the signs that read, "No Smoking Permitted in This Carriage."
The general tenor of his lengthy correspondence was to discover just what was this "No Smoking" that was permitted in certain carriages, and whether it might be injurious to his health. (At no time did he suggest that their use of English might be faulty.)
The company, aparently, went to great lengths to convince him that there was nothing for him to fear, but as they refused to acknowledge - if, indeed, they realised - that the notice was badly phrased, they merely dug themselves into an ever deeper morass of mutual misunderstanding.
