: British / American language mishmash English is not my mother tongue. I am completely fluent in English though, and I write my fiction in English. Here's the problem: I live in neither the

The differences between British and American English (Standard Written English) vary in degree from region to region. Many British words, like Autumn, are easily understood because they are used as part of a regional dialect as well. The people who settled the American Colonies brought their language and idioms, changing only slightly over the years.

I am an American living in Canada and have daily exposure to the essentially British English spoken here.

Mixing the two variants will not confuse native speakers as most have had some exposure to the other English. What might seem jarring is if you have an American character who uses many British idioms without a backstory of studying abroad etc.

Context is your friend. When reading Tale of Two Cities, the word qeue had me pause for a second, but it was clear the character was standing in a line, so idiom learned and off I went.

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I'm a native speaker of American English and my reaction to various British expressions can vary considerably on the expression:

There are some words and expressions that don't sound British, at least to me (despite people saying they are). They sound normal and therefore are easily understood. For example: autumn, kerfuffle, wonky.
Some British expressions sound British, though they are easy to understand. Some examples are: blimey, bloody, bollocks, rubbish.

Likewise there are some American expressions that most Americans should recognize as being American: y'all, dude, man (as an exclamation).

With some British expressions (either in general or in a specific context), I just don't know the meaning. For example, "in the skip" or "scarper". The context might be enough to work out the expression. It might not. All I know is that practically nobody is going to be reaching for a dictionary when they want to be reading, especially not native speakers.

The metric system is similar; I know what type of measurement a unit is, but not how to translate it exactly into units I understand. This is particularly true for kilograms but I'm a little better with meters.

And then there are your false friends. These are the expressions that are used in the same contexts in both dialects, yet mean different things. "Tabling a discussion", "football", and "pudding" are all examples. I would also include shorthand dates (e.g. 12/7/13) in here. I've found that even when I know that British people never talk about (for example) American Football, I always jump to that conclusion when I hear "football".
Some British expressions sound ungrammatical (enough to make me question if it's a native speaker's writing), maybe because they are not used often enough for me to have ever heard it. For example, "have a walk" sounds weird to me. As does "in future".
And then there are words which are acceptable in one dialect that are very offensive in the other (e.g. fanny, fag). There aren't too many expressions that fall into this category though.

My suggestion is to write so that nobody notices the language you're using; nothing should stick out in the way of language unless it absolutely has to (e.g. no getting around spelling). My other suggestion is to stay away from slang and overly informal language as much as possible.

Recognizably American or British expressions will look out of place in your setting. Whether they're recognizable as such depends on who's reading. Unfortunately (as my mostly one sided examples imply) not even native speakers are very good at realizing what dialect specific parts of their dialect there are.

You could always try doing research (the list of words given by Wikipedia would be a good start) but after some amount of time the returns are gong to be diminishing. Remember, the differences are not just vocabulary: it's also grammar. You will likely need both an American and a British beta reader.

In practice, sometimes the differences are significant enough that a publisher will invest time in localizing from one dialect to another. This could also be an option for you.

Probably one of the most famous examples is Harry Potter: it was originally written in British English and was later localized into American English. A pretty good list of the changes made between the versions can be found here, which is worth checking out. What I've noticed is that British expressions are really only retained in dialogue, which makes sense because the characters are British. This also includes the British accents, which don't really mean much to an American.

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I have the exact same problem with the English language. Although, to make it worse (or better), I have an European character (who studied British English) living in the USA. Whenever the chapter is written from the European character's POV, I do not have to worry about the mish-mash - it's part of the character's speech pattern (other characters have pointed out some British words, like the infamous 'a rubber', so it's all good). But I have a lot of chapters from American characters' POV... oh, and the occasional actually 'British' chapter.

Here's the solution:

1) make a cheat sheet

Go online and mash together all the British vs American English words lists you can find (not all of them have the exact same words). Mix it all together. Do the same for the idioms, though that's not as common. Study them. Just picture yourself back at school, yay!

If you attained your English fluency with books and films from Australia and Canada, add those English varieties to your cheat sheet. Moreover, add to your list any regional particularities you come across, even within the US (eg. you all vs you guys... vs even the Irish ye).

2) invest on a spelling checker that differentiates the two

I believe you'll have to pay for one though. On the other hand, you won't have to worry one bit since the app will do the hard work for you.

3) go for 'universal English'

This approach is the trickiest, as you won't find as much information. The idea is to avoid words and idioms that belong to a definitive variety, favouring the ones most used by non-native speakers.

[edit] 4) use NGram viewer

Whenever you want to quickly check how American or British a word or expression is, go for the NGram viewer.

You mention you write using British spelling, the American one feeling off. To me, this means you probably studied (and primarily learnt) British English. There are a few grammatical differences between the two - a good university level grammar for language learners will explain those differences - so you may want to check what comes natural to you in that level too.

My advice for your particular case is to write in the variety you feel more comfortable with. Let the publisher worry about 'translating' it to the other variety when the time comes (if need be - British and American are really not so different if you compare them to other languages such as European and Brazilian Portuguese).

Where it comes to the characters' speech patterns, you may wish to make them sound 'mish-mashy' on purpose. Theoretically, it might signal that the fantasy language is not a 'real earth-country specific language'. Of course, that would have to be pointed out in a 'before' or 'after word' and, naturally, a few native speakers would have to tell you how odd it might feel. On the other hand, you may wish to have characters from a certain area sound more British, and others more American.

But do write in the variety you're more comfortable with. If that variety ends up being the mish-mashy one, so be it. In that case, worry about BrE vs AmE only when editing - and the app that picks up English varieties will be a HUGE help. Believe me. I know.

PS Edit:

While I can't speak for how odd an English mish-mash will sound to native ears, I can tell you that mixing two varieties of Portuguese is incredibly jarring. Of course European and Brazilian Portuguese have very different grammar structures ('saw me' is 'viu-me' in European and 'me viu' in Brazilian) and a greater number of vocabulary changes (lift vs elevator kind of changes). Still, assume there is a level of 'jarringness' and avoid the mish-mash unless there is an in-world explanation (a character's speech pattern, a fantasy world's speech pattern). And, if you do go for the mish-mash, then avoid aggressively American or British idioms (that is, ones which aren't often used in a world-wide setting and that are opaque for most people outside the country originating the idiom).

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I am an American, and I use American English. I have read British literature before, but the British books that I have read are all written before the 20th century; and I read them for English classes. From my perspective, British books are, for the most part, intelligible to me. I just read the book like an American novel.

Language and culture are intertwined. If you want to write completely in American English, then you may want to befriend an American. You can do so on an app called HelloTalk. This app allows you to make friends with people from all over the world. You share your language; your friend shares the language you are interested in. The more you know American culture, the less of an impact those British stuff will have on you. Then, someday in the future, you share your story with your American friend. Your friend will proofread for you. If something sounds funky or looks funky, then it probably is, and your American friend will raise an eyebrow. Let your American friend make some adjustments. Then, you look over the changes and create your final draft.

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