As an American who spent only a little time in London (a couple months), I think I understand this as a joke about the trashy street talk which is both incomprehensible and humorous to Americans, made more absurd by the irony of putting it on an official-looking form.
Mostly, I think Americans love making fun of the surprising gap between the posh arrogance of the British as depicted in movies compared to the trashiness of the lowbrow lifestyle we've come to realize is quite common in modern England. Also, the thought that people actually use these words in conversation is hilarious.
Mostly, I think Americans love making fun of the surprising gap between the posh arrogance of the British as depicted in movies compared to the trashiness of the lowbrow lifestyle we've come to realize is quite common in modern England. Also, the thought that people actually use these words in conversation is hilarious.