Level of difficulty: Easy
Have you heard of the term lingua franca? It's a Latin phrase, but you can use it in English. It comes from Latin, and literally means "French language": it is used nowadays to mean a common language between people who do not speak the same language. In the 18th century, French was the language of international diplomacy: that's the origin of this term.
Nowadays, English is the international lingua franca. What makes English truly unique is that there are more non-native speakers in the world than there are native speakers. How ironic that English has become literally a "French language"! Although it unites the world, there are regional variations of English that persist, and which you should be aware of.
American (US) and British (UK) English are the two most common systems of written and spoken English. American English is the English of the USA; British English is the English of the UK. Many countries of the British Commonwealth (Canada, Australia, New Zealand, etc.) originally favored UK English, but have since diverged, with country-specific variations in spelling and style. Australian English is very similar to UK English, with a few words permitting American spelling (e.g., "inquire" instead of "enquire"). Canadian English retains UK spelling for many words, but American spellings are also common because of geographical proximity.
Example 1 (US): We inquired whether participants were taking estrogen supplementation.
Example 2 (UK): We enquired whether participants were taking oestrogen supplementation.
Example 3 (Aus): We inquired whether participants were taking oestrogen supplementation.
Example 4 (Can): We enquired whether participants were taking estrogen supplementation.
The most noticeable variations in written English are punctuation and spelling. A common instruction from academic journals is for authors to use “either US English or UK English, but not a mixture”. Increasingly common is "English in academic style": basically, the author should choose his or her preferred system. Because requirements vary from journal to journal, it is essential that you check a journal's Author Guidelines page to determine an appropriate English system before editing and submitting your manuscript.
Example 1: (Nature publications) Oxford UK English spelling.
http://www.nature.com/ncomms/authors/submit.html
Example 2: (IEEE publications) Change all British spellings to American spellings where applicable.
http://www.ieee.org/about/webteam/styleguide/mainsite_content.html
Example 3: (e.g. Journal of Endocrinology) Manuscripts can be written in either UK or US English.
http://joe.endocrinology-journals.org/site/misc/For-Authors.xhtml
US spelling and grammar is a safe choice for the majority of international publications. UK-based publishing companies (e.g., Oxford University Press) usually prefer UK spelling. Local publications in Canada or Australia will sometimes adhere to their version of English. For example, if you are writing your thesis for an Australian university, writing in Australian English is the way to go.
If the journal does not specify the spelling system, we recommend US or UK spelling.
One final note: native speakers like to play up differences between variants of English, saying UK English is the ‘true’ English since it England is the land of its origin, or that US English is the best to learn because of the US's global reach. However, in a globalized world, many of these differences correspond to cultural identity rather than meaning. A wise author will rise above such simplistic judgments and familiarize him or herself with the details of each English system for publishing purposes.
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Variants of World English — American and British
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