One English problem that causes confusion in Hong Kong is the British and American systems of counting floors in a building. To add to the problem Hong Kong has its own variation on counting floors. Consider this conversation.
Old China hand: The shop you want is on the second floor.
American English speaker: Thanks.
British English speaker: You told me that the shop is on the first floor.
Old China hand: Yes, that's right the shop is on the first floor.
American English speaker: Which floor should I be going to?
Old China hand: Go to the second floor.
In this conversation the old China hand is fluent and can use both counting systems without difficulty. It is the speakers of only British or American English who do not understand.
I once spent an entire year supervising the wrong floor of a school every morning and making sure the students were well behaved. (They were.) I had been told to supervise the third floor. Since I can read Chinese numbers I went to the third floor, which was marked 三樓 (the third floor). However the principal was using British English, for my convenience, and meant 四樓 (the fourth floor).
In British English the floor of a building that you walk into from the ground is called the ground floor. The next floor above it is called the first floor and the floor below is called the basement. In American English, however, the floor of a building that you walk into from the ground is called the first floor or the ground floor. The floor above this ground floor is always called the second floor, which of course, is the first floor for the British. The floor below ground level is called the basement, as it is in British English.
In Hong Kong buildings are mixed. Some number floors in British English and others in American English. Many buildings use two systems which can be confusing when you see both 1st floor in English and 二樓 (2nd floor) in Chinese. To add to that many Hong Kong buildings count floors from a main floor called a podium. Also many Hong Kong buildings have been built on slopes because of the shortage of land. So the ground floor on one side of the building may be the second floor on the other side. This situation has caused some building owners to number their floors, ground 1, ground 2, lower ground 2, upper ground 1 and so on. That way more stores can be on the ground floor.
Then there are lucky and unlucky numbers. 13 is unlucky in the West and so is 4 in Cantonese society. The number 4 sounds like death. Many building owners tend to skip floors with unlucky numbers. So my building has no 4th, 13th, 14th or 24th floor. Some buildings will add extra 8th floors, since 8 is good luck in Cantonese society. 8 sounds like prosperity; so some buildings have 88th and 888th floors, no matter how high they really are.
There is also a spelling problem. The word storey in British English or story in American English describes the number of floors. The plurals are storeys and stories. Thus we say that a building has eighteen storeys, or is an eighteen-storey building. Remember to add the hyphen, because the similarly spelt and sounding word story (plural "stories") is used in American English. Of course a story is also a description of something that happened, whether imaginary or true.
Building owners can use any of these combinations to number their buildings and they are not wrong, even if someone else numbers their building differently. A competent Hong Kong English speaker should be able to use both American and British systems and the Hong Kong variations.