We can all be speaking the same language but depending on where we grew up the same words can have very different meanings depending where you are geographically. Or some items just have totally different names like swimming costume verses bathing suit, running shoes verses sneakers, pants verses underwear, bathroom verses the loo, etc. Using expressions that are common in your country may not work when writing copy for a more global audience.
When I take on a new project, along with the general questions revolving around developing the content brief, I always ask, UK or American spelling? Here in Dubai, it's usually UK but there are always exceptions to every rule, right?
(note: Tupperware is probably a term that not everyone is familiar with either...it's a very popular brand name of a maker of plastic containers of varying sizes and a variety of kitchen implements)