Wikipedia:Plain English

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An encyclopedia article is a piece of expository prose, and as such it has an objective purpose. This purpose is not to impress its readers with your learning or vocabulary, even if that is your subjective purpose for writing it. Instead, its purpose is to impart information, whether by introducing new knowledge to people who lack it or by reminding people of what they had half-forgotten. Plain words best serve this purpose.

As William Strunk put it:

Vigorous writing is concise. A sentence should contain no unnecessary words, a paragraph no unnecessary sentences, for the same reason that a drawing should have no unnecessary lines and a machine no unnecessary parts. This requires not that the writer make all his sentences short, or that he avoid all detail and treat his subjects only in outline, but that every word tell.

Ernest Gowers gave many examples of writing that could be improved. This is one from the UK Government about police complaints procedures:

As Gowers says, "Here is a translation ... [which has] made the sentence far clearer, and at the same time exactly halved the number of words":

Use all the words you need, but no more.

Jargon and technical vocabulary are inevitable in many fields. Whenever using them, explain them briefly or give a to help the reader understand the word.

For example, a legal word like estoppel may confuse a reader who is not a lawyer. Estoppel essentially means that "the law is not amused when you contradict yourself, whether by words or actions, after someone has acted on what you said before"; however, the scholastic method of the law has clouded its meaning over time. The estoppel article should clarify both these points for readers and allow them to understand the word in context.

More is valuable in these situations. As a writer, include some history of the problem the theorem was meant to solve or cite practical applications of the theorem. This sort of information allows a non-mathematician to retain knowledge from the mathematical article.

To call someone a terrorist is a value judgment; tell us instead that he bombed the subway and that his compatriots issued a statement containing political demands, and you are as close to neutrality as mere mortals have the power to achieve. Concrete words are inherently less pointed than any labels, and the truer path to neutrality is to replace the abstract with the concrete.

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