Standard written English refers to the preferred form of English as it is written according to prescriptive authorities associated with publishing houses and schools. As there is no regulatory body for the English language, there is some disagreement about correct usage, though there is enough agreement that the written form of English is relatively transcendent of dialectal variation. In addition to being used in written media such as books and newspapers, it is also the basis of Signed English.
John H. Fisher, author of The Emergence of Standard English, observes that in Spanish, Italian, French, and English, the written languages became standardised before the spoken languages, and that these provide frames of reference for what is considered standard speech. He said, in an interview for the Children of the Code project:
I came to the conclusion that all of the discussion of standardisation of language was a discussion of the written forms of language. It had nothing to do with spoken language. We don't have the spoken language standardised yet. When we say that we're speaking Standard English, what we're doing is transferring into our spoken vocabulary and syntax the elements of the written language. What is standard in what you and I are talking now is what we get from our writing.
There are grammatical constructions and words that one uses in speech that one generally avoids in written compositions. Even in the most colloquial of online chats, interjections such as "like" are rarer than in speech.
Stephen Fry stated his view on the exclusivities of Written English in an anonymous essay on Wodehouse:
The language, however, lives and breathes in its written, printed form. Let me use an example, taken at random. I flip open a book of stories and happen on Bertie and Jeeves discussing a young man called Cyril Bassington-Bassington.
Well, try as hard as actors might, such an exchange will always work best on the page.
Indeed, Wodehouse uses this aspect of the written language when the name "Psmith" is explained on the page as being "Psmith" with a silent "P" as in "Pshrimp." This humour cannot be translated into the spoken word.