We British pronounce it wrongly, given that vitamins means vital amines.
There hasn't been much mention on here of English-speakers from all English-speaking countries having bad spelling.
In Polish, it seems you can't just learn one form of the word and know how it works in all cases and instances. Likewise, in English, you have to learn it at least twice - once for the spelling and again for the pronunciation.
picture-writing of Chinesebed
is a good word for this.