The official name for the sodium chloride which we can eat, is actually 'table salt'. But only if you are strictly talking about chemistry then Crimsoncross is correct, because it is rarely referred to as such. The only reason it is not simply called 'salt' is because there are hundreds of different salts, such as potassium dichromate which is definitely not something you want to be adding to your food. You're all right in effect however
Ehm sodium is the odd one out here, I believe only english (both of them) does not use the word natrium, other languages do. And yes not mercury but a translation of quicksilver is used in other languages, and kalium not potassium. When someone says oxygen, do you say they speak latin? They are just the names for the elements, they are, what they are called. A few just deviate from how it is written in other language (i.e. remained their original name)