Al over at Big Al's Books and Pals muses on the difference in the spelling and slang between American English and other versions of the English language.
As most of us know, paperbacks published in different territories are always copy-edited so that the text reflects the spelling, grammar and punctuation common in the country of publication, rather than the country of origin of the writer, though vocabulary is not usually changed (except, as I understand it, in children's books).
With ebooks, it is now quite common for one edition to be published in all markets - particularly in the case of self-published ebooks available via Amazon's Kindle store or Barnes & Noble (though B&N won't let you publish direct to their Nook store unless you have a US bank account, which presumably cuts down the number of non-American books available to their readers).
The question in some readers' minds, when they're choosing a book to buy, is whether a self-published book will be any good - or whether it might have been turned down by a publisher because the writer has no talent for writing. One way a reader will make up their mind about that is by looking at a sample of the work. Is it full of homophones? Is the punctuation OK? Most will appreciate that vocabulary differs from country to country, and will be able to get the meaning of the word from its context. But they won't be impressed if it appears that the writer can't follow the basic rules of grammar. Except that the rules are slightly different in different English-speaking countries. I can't see any way round this other than to give the writer the benefit of the doubt when reading. Actually, giving the other person the benefit of the doubt is a good policy generally, isn't it.
Here's a picture of some Midget Gems for any of Al's readers who are not familiar with these chewy sweets. Though, like Al, if you read my book, Three Sisters, and had never seen a packet of Midget Gem, you probably guessed what they might look like.
You can read his post here.