More or less everybody except US and Russia has zero floor, counting in big office buildings is fun: 3,2,1,-1,-2, I know... The concept of a number zero is not that old (couple hundred years, don't remember the details), but should be enough to update your language :-*
I see. Weird that our so similar languages differ like this. But our counting systems are also vastly different, so maybe it isn't so weird anyway?
Sometimes we can have the entrance in a basement which would then be denoted as the basement and not the first floor. I guess the basement example is when what the british names ground floor is partially underground. In all other cases our first floor is where the main entrance is.
Therefore "more or less" ;) of course I didn't make a study on it, just traveled a bunch of countries and only in thosei noticed it... Needing to add that this is not something that would jump in my eye first time I visit a county.
On a side note: in Germany, we use the -2, -1, 0, 1, 2 scheme, bit most of the times they write it more clear with: 1. OG (first upper floor), EG (ground floor), 1. UG (First lower floor). I think "upper" and "lower" is not a good translation, but I'm now to tired to think of someone better suiting
Kind of, yes, but I feel the Norwegian word "etasje" is better translated to "storey" than "floor". Taking that translation, we're saying "first storey, second storey, etc." rather than "first floor, second floor, etc." which I guess everybody can agree makes sense.