A lady from France staying in England needed some help with translation. She was used to using a cigarette holder when smoking, but didn't know what they were called in English. She asked her English friend who decided to have a laugh at her expense. They are called french letters over here, she was told, and you buy them from the chemist.
So off she went to her local Boots and asked the assistant for a french letter. The assistant explained that they were available in different sizes, and which size would she like.