The majority of style guides that use a Latin-derived alphabet as a language base now prescribe or recommend the use of a single space after the concluding punctuation of a sentence.
Style guides are important to writers since "virtually all professional editors work closely with one of them in editing a manuscript for publication".
Additionally, the Duden, the German-language dictionary most commonly used in Germany,[9] indicates that double sentence spacing is an error.
[15] In Canada, both the English and French language sections of the Canadian Style, A Guide to Writing and Editing (1997), prescribe single sentence spacing.
[27] The Turabian Style, published as the Manual for Writers of Research Papers, Theses, and Dissertations, is widely used in academic writing.
The 7th Edition, published in 2007, stipulates that the use of periods, question marks, and exclamation points as "terminal punctuation" to end a sentence should be followed by a single space.
[28] Until the early 2000s, the Modern Language Association (MLA) left room for its adherents to single or double sentence space.
Publications in the United States today usually have the same spacing after concluding punctuation marks as between words on the same line.
Since word processors make available the same fonts used by typesetters for printed works, many writers, influenced by the look of typeset publications, now leave only one space after a concluding punctuation mark.
In addition, some publishers' guidelines for preparing a manuscript's electronic files ask professional authors to type only the spaces that are to appear in print.
[31] This recommendation does not apply "to the published, or final version, of a work", where the spacing convention is determined by the publication designer.
According to The Chicago Manual of Style, The Bluebook is the "most widely used [legal] citation guide" in the United States.
"[39] Various other legal style guides provide non-committal positions on this topic, such as the 2006 version of the ALWD Citation Manual, which has been "widely adopted by law-school writing courses".
[40] This guide provides limited coverage on punctuation, referring readers to other style manuals that prescribe single sentence spacing.
[44] Of the legal style guides listed in this section, all use proportional fonts with a single space between sentences in their text.
For example, the 2009 edition of the Associated Press Stylebook calls for a single space following the terminal punctuation of a sentence.
[47] For copyeditors, the 2nd edition of the Copyeditor's Handbook: A Guide for Book Publishing and Corporate Communications, published in 2006, states that users should "delete any extra word spacing before or after punctuation marks" and that "The conventions are: One space follows a sentence-ending punctuation mark.
Most works identify the Courier 12-point font as the industry "standard" for manuscripts, such as the Screenwriter's Bible: A Complete Guide to Writing, Formatting, and Selling Your Script.
[57] All of these works illustrate single sentence spacing in their manuscript examples, regardless of font type.
The 2008 edition of the Web Style Guide does not discuss spacing after the terminal punctuation of a sentence, although it provides a chapter on typography.
In this section, the authors assert "the basic rules of typography are much the same for both web pages and conventional print documents.