User:Battling McGook/Sentence spacing



Sentence spacing is the horizontal space between sentences in typeset text. Since the introduction of movable-type printing in Europe, varying sentence spacing has been used in languages with a Latin-derived alphabet. Throughout history, most printed texts have used wider spacing between sentences than that used between words, however word spacing was not uncommon. During the 20th century, the use of word spacing between sentences has become much more common, overtaking wider spacing in printed text. There has been much debate about why this has happened, and whether this trend is a standard that people should follow, or simply a style choice that happens to be more popular right now.

Until the 20th century, printing house and printers in many countries used wider spacing between sentences. There were exceptions to this traditional spacing—printers sometimes preferred word spacing. Traditional printing methods allowed printers to vary the spacing between words and sentences in tiny increments, allowing them to basically set spacing to any desired width. With the introduction of the typewriter however, people were only had one single space available that was the same size as all of the letters. In order to replicate the wider sentence spacing used in most printing, people were taught to press the spacebar twice between sentences. This also changed the way we thought about space, as something to be counted rather than measured. With the computer age, this has continued, as we still only have one space character on standard keyboards. Much of the debate today seems to center around how many spaces should be used, rather than how much space, and given the differences between plain text and formatted text, it isn't clear if they should be considered to be the same issue.

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These include a word space (as between the words in a sentence), a single enlarged space, two full spaces, and, most recently in digital media, no space. Although modern digital fonts can automatically adjust a single word space to create visually pleasing and consistent spacing following terminal punctuation, most debate is about whether to strike a keyboard's spacebar once or twice between sentences.

Until the 20th century, publishing houses and printers in many countries used single, but enlarged, spaces between sentences. There were exceptions to this traditional spacing method—printers in some countries preferred single spacing. This was French spacing—a term synonymous with single space sentence spacing until the late 20th century. Double spacing, or placing two spaces between sentences (sometimes referred to as English spacing), came into widespread use with the introduction of the typewriter in the late 19th century. It was felt that with the monospaced font used by a typewriter, "a single word space ... was not wide enough to create a sufficient space between sentences" and that extra space might help signal the end of a sentence. This caused a widespread change in practice. From the late 19th century, printers were told to ignore their typesetting manuals in favor of typewriter spacing; Monotype and Linotype operators used double sentence spacing and this was widely taught in typing classes.

With the introduction of proportional fonts in computers, double sentence spacing became obsolete, according to many experts. These proportional fonts now assign appropriate horizontal space to each character (including punctuation marks), and typesetting programs such as TeX can modify kerning values to adjust spaces following terminal punctuation, so there is less need to increase spacing manually between sentences. From around 1950, single sentence spacing became standard in books, magazines and newspapers. Regardless, many still believe that double spaces are correct. The debate continues, notably on the World Wide Web—as many people use search engines to try to find what is correct. Many people prefer double sentence spacing for informal use because that was how they were taught to type. There is a debate on which convention is more readable, but the few recent direct studies conducted since 2002 have produced inconclusive results.

Much modern literature on typography says that double spacing is not desirable, but some non-typographical sources indicate that it could be used on a typewriter or with a monospaced font. The majority of style guides opt for a single space after terminal punctuation for final and published work, with a few permitting double spacing in draft manuscripts and for specific circumstances based on personal preference. Grammar and design guides, including Web design guides, provide similar guidance.

Traditional typesetting


Early printing systems were limited to inflexible word spacing. Improvements that allowed variable spacing soon appeared. Early American, English, and other European typesetters' style guides (also known as printers' rules) specified spacing standards that were all essentially identical from the 18th century onwards. These guides—e.g., Jacobi in the UK (1890) and MacKellar, Harpel, and De Vinne (1866–1901) in the U.S. —indicated that sentences should be em-spaced, and that words should be 1/3 or 1/2 em-spaced (illustration right). Only a single type block was typically used, which resulted in the appearance of about a double word space between sentences. For most countries, this remained the standard for published work until the 20th century. Yet, even in this period, there were publishing houses (notably in France) that used a standard word space between sentences—a technique called French spacing (illustration below).

Mechanical type and the advent of the typewriter
Mechanical type systems introduced near the end of the 19th century, such as the Linotype and Monotype machines, allowed variable sentence spacing. However, with the advent of the typewriter and its widespread usage beginning in the late 19th century, the average text composer had only two possibilities—to strike the space bar once or twice between sentences. Most typewriters' mechanical limitations did not allow variable spacing. (Several models of proportional-spacing typewriters have been manufactured, but they were always a minority.) This caused a fundamental change in sentence spacing methods. Typists in some English-speaking countries learned to insert two spaces between sentences to approximate the exaggerated sentence spacing used in traditional printing, a practice that continued throughout the 20th century. This became known as English spacing, and marked a divergence from French typists, who continued to use French spacing.

Transition to single spacing
Professional printers moved from double to single sentence spacing in the 20th century. Magazines, newspapers, and books began to adopt the single space convention in the United States in the 1940s and in the United Kingdom in the 1950s. Typists did not transition to single spacing simultaneously. The average writer still relied on the typewriter to create text—with its inherent mechanical spacing limitations.

Technological advances began affecting sentence spacing methods. In 1941, IBM introduced the Executive, a typewriter capable of proportional spacing —which had been used in professional typesetting for hundreds of years. This innovation broke the hold that the monospaced font had on the typewriter—reducing the severity of its mechanical limitations. "By the 1960s, electronic phototypesetting systems" ignored runs of white space in text. This was also true of the World Wide Web, as HTML ignores additional spacing, but this is due to a limitiation of the underlying technology, and the lack of any tags to indicate sentence structure. Computers offered additional sentence spacing tools for the average writer, and the double spacing convention, "as a standard operating procedure ... went out with the IBM Selectric". By the late 20th century, literature on the written word had begun to adjust its guidance on sentence spacing.

Typography
Early positions on typography (the "arrangement and appearance of text") supported traditional spacing techniques in English publications. In 1954, Geoffrey Dowding's book, Finer Points in the Spacing and Arrangement of Type, underscored the widespread shift from a single enlarged em space to a standard word space between sentences.

With the advent of the computer age, typographers began deprecating double spacing, even in monospaced text. In 1989, Desktop Publishing by Design stated that "typesetting requires only one space after periods, question marks, exclamation points, and colons", and identified single sentence spacing as a typographic convention. Stop Stealing Sheep & Find Out How Type Works (1993) and Designing with Type: The Essential Guide to Typography (2006) both indicate that uniform spacing should be used between words, including between sentences.

More recent works on typography weigh in strongly. Ilene Strizver, founder of the Type Studio, says, "Forget about tolerating differences of opinion: typographically speaking, typing two spaces before the start of a new sentence is absolutely, unequivocally wrong." The Complete Manual on Typography (2003) states that "The typewriter tradition of separating sentences with two word spaces after a period has no place in typesetting" and the single space is "standard typographic practice". The Elements of Typographic Style (2004) advocates a single space between sentences, noting that "your typing as well as your typesetting will benefit from unlearning this quaint [double spacing] Victorian habit."

David Jury's book, About Face: Reviving the Rules of Typography (2004)—published in Switzerland—clarifies the contemporary typographic position on sentence spacing:

"Word spaces, preceding or following punctuation, should be optically adjusted to appear to be of the same value as a standard word space. If a standard word space is inserted after a full point or a comma, then, optically, this produces a space of up to 50% wider than that of other word spaces within a line of type. This is because these punctuation marks carry space above them, which, when added to the adjacent standard word spaces, combines to create a visually larger space. Some argue that the 'additional' space after a comma and full point serves as a 'pause signal' for the reader. But this is unnecessary (and visually disruptive) since the pause signal is provided by the punctuation mark itself."

Style guides
Early style guides for typesetting used a wider space between sentences than between words— "traditional spacing," as shown in the illustration to the right. During the 20th century, style guides commonly mandated two spaces between sentences for typewritten manuscripts, which were used prior to professionally typesetting the work. As computer desktop publishing became commonplace, typewritten manuscripts became less relevant and most style guides stopped making distinctions between manuscripts and final typeset products. In the same period, style guides began changing their guidance on sentence spacing. The 1969 edition of the Chicago Manual of Style used em spaces between sentences in its text; by the 2003 edition it had changed to single sentence spacing for both manuscript and print. By the 1980s, the United Kingdom's Hart's Rules (1983) had shifted to single sentence spacing. Other style guides followed suit in the 1990s. Soon after the beginning of the 21st century, the majority of style guides had changed to indicate that only one word space was proper between sentences.

Modern style guides provide standards and guidance for the written language. These works are important to writers since "virtually all professional editors work closely with one of them in editing a manuscript for publication." Late editions of comprehensive style guides, such as the Oxford Style Manual (2003) in the United Kingdom and the Chicago Manual of Style (2010) in the United States, provide standards for a wide variety of writing and design topics, including sentence spacing. The majority of style guides now prescribe the use of a single space after terminal punctuation in final written works and publications. A few style guides allow double sentence spacing for draft work, and the Gregg Reference Manual makes room for double and single sentence spacing based on author preferences. Web design guides do not usually provide guidance on this topic, as "HTML refuses to recognize double spaces altogether". These works themselves follow the current publication standard of single sentence spacing.

The European Union's Interinstitutional Style Guide (2008) indicates that single sentence spacing is to be used in all European Union publications—encompassing 23 languages. For the English language, the European Commission's English Style Guide (2010) states that sentences are always single-spaced. The Style Manual: For Authors, Editors and Printers (2007), first published in 1966 by the Commonwealth Government Printing Office of Australia, stipulates that only one space is used after "sentence-closing punctuation", and that "Programs for word processing and desktop publishing offer more sophisticated, variable spacing, so this practice of double spacing is now avoided because it can create distracting gaps on a page."

National languages not covered by an authoritative language academy typically have multiple style guides—only some of which may discuss sentence spacing. This is the case in the United Kingdom. The Oxford Style Manual (2003) and the Modern Humanities Research Association's MHRA Style Guide (2002), state that only single spacing should be used. In Canada, both the English and French language sections of the Canadian Style, A Guide to Writing and Editing (1997), prescribe single sentence spacing. In the United States, many style guides—such as the Chicago Manual of Style (2003)—allow only single sentence spacing. The most important style guide in Italy, Il Nuovo Manuale di Stile (2009), does not address sentence spacing, but the Guida di Stile Italiano (2010), the official guide for Microsoft translation, tells users to use single sentence spacing "instead of the double spacing used in the United States".

Language guides
Some languages, such as French and Spanish, have academies that set language rules. Their publications typically address orthography and grammar as opposed to matters of typography. Style guides are less relevant for such languages, as their academies set prescriptive rules. For example, the Académie française publishes the Dictionnaire de l'Académie française for French speakers worldwide. The 1992 edition does not provide guidance on sentence spacing, but is single-sentence-spaced throughout—consistent with historical French spacing. The Spanish language is similar. The most important body within the Association of Spanish Language Academies, the Real Academia Española, publishes the Diccionario de la Lengua Española, which is viewed as prescriptive for the Spanish language worldwide. The 2001 edition does not provide sentence spacing guidance, but is itself single sentence spaced. The German language manual Empfehlungen des Rats für Deutsche Rechtschreibung ("Recommendations of the Council for German Orthography") (2006) does not address sentence spacing. The manual itself uses one space after terminal punctuation. Additionally, the Duden, the German language dictionary most commonly used in Germany, indicates that double sentence spacing is an error.

Grammar guides
A few reference grammars address sentence spacing, as increased spacing between words is punctuation in itself. Most do not. Grammar guides typically cover terminal punctuation and the proper construction of sentences—but not the spacing between sentences. Moreover, many modern grammar guides are designed for quick reference and refer users to comprehensive style guides for additional matters of writing style. For example, the Pocket Idiot's Guide to Grammar and Punctuation (2005) points users to style guides such as the MLA Style Manual for consistency in formatting work and for all other "editorial concerns". The Grammar Bible (2004) states that "The modern system of English punctuation is by no means simple. A book that covers all the bases would need to be of considerable breadth and weight and anyone interested in such a resource is advised to consult the Chicago Manual of Style."

Digital age
Mignon Fogarty, "Grammar Girl", points out that in the past typewriting used two spaces—in deference to its monospaced font limitations—but "Now that most writing is done on computers it is no longer necessary to type two spaces after a period at the end of a sentence." She answers the question of "How many spaces?" as follows: "On a typewriter, use two. On a computer, use one." This position highlights the late 20th-century transition from the typewriter to the computer, and its effect on sentence spacing.

Today, computers and digital fonts allow sentence spacing variations not possible with the typewriter. Proportional fonts are widely available to average computer users. Computer-based tools such as proportional fonts, kerning, computer-based word processors, and software such as TeX allow users to arrange text in a manner previously only available to professional typesetters. The World Wide Web eliminates all repeated spaces because of the characteristics of HTML, although this can be viewed as a limitation of the underlying technology, and as such it doesn't offer the same fine-grained control of spacing as other modern software. Yet, even in the digital age, many school students are still taught to strike the space bar twice between sentences when using computers, contributing to confusion regarding sentence spacing in the 21st century.

The text editing environment in Emacs uses a double space following a period to identify the end of sentences unambiguously; the double space convention prevents confusion with periods within sentences which signify abbreviations. How Emacs recognizes the end of a sentence is controlled by the settings sentence-end-double-space and sentence-end.

Controversy
James Felici, author of the Complete Manual of Typography, says that the topic of sentence spacing is "the debate that refuses to die ... In all my years of writing about type, it's still the question I hear most often, and a search of the web will find threads galore on the subject". This subject is still widely debated today because many typists were taught to use double sentence spacing in school. As a result, there is a common belief that double sentence spacing is "correct", even given modern technology and proportional fonts. This is similar to other typewriter conventions, practiced in deference to the typewriter's "severe technical limitations", that are still used by writers. These include the use of prime marks (or "dumb quotes") for quotation marks, underlining words in place of italics, and using hyphens to approximate en and em dashes.

Many people are opposed to single sentence spacing for various reasons. Some state that the habit of double spacing is too deeply ingrained to change. Others claim that additional space between sentences makes text "look better" or easier to read. Proponents of double sentence spacing also state that some publishers may still require double spaced manuscript submissions from authors. A key example noted is the screenwriting industry's monospaced "standard" for screenplay manuscripts, Courier, 12-point font, although some works on screenwriting indicate that Courier is merely "preferred," and that proportional fonts may be used. Some reliable sources state simply that writers should follow their particular style guide, but proponents of double spacing caution that publisher's guidance takes precedence, including those that ask for double sentence spaced manuscripts.

In opposition to these ideas, many experts state that double sentence spacing was only relevant when faced with the limitations of the typewriter, and is now obsolete for most uses, especially given the capabilities of modern computers and digital fonts. While typewriter users had only two choices (to strike the space bar once or twice), modern proportional fonts allow compositors to manually adjust sentence spacing to thousandths of an inch for visually pleasing typesetting. Some sources state it is also acceptable even for monospaced fonts to be single spaced today, although other references specify double spacing for monospaced fonts. Another opinion is that as terminal punctuation marks the end of a sentence, and additional spacing is itself punctuation, additional spacing is redundant.

The double space typewriter convention was taught in schools in typing classes, and that remains the practice in many cases. Some voice concerns that students will later be forced to relearn how to type. Most style guides indicate that single sentence spacing is proper for final or published work today, and "most publishers" require manuscripts to be submitted as they will appear in publication—single sentence spaced. Writing sources typically recommend that prospective authors remove extra spaces before submitting manuscripts; although other sources state that publishers will use software to remove the spaces before final publication. Finally, some experts state that, while double spacing sentences in unpublished papers and informal use (such as e-mail) might be fine, double sentence spacing in desktop-published (DTP) works will make the final result look "unprofessional" and "foolish".

Effects on readability and legibility
Claims abound regarding the legibility and readability of the single and double sentence spacing methods—by proponents on both sides. Supporters of single spacing assert that familiarity with the current standard in books, magazines, and the Web enhances readability, that double spacing looks strange in text using proportional fonts, and that the "rivers" and "holes" caused by double spacing impair readability. Proponents of double sentence spacing state that the extra space between sentences enhances readability by providing breaks between sentences and makes text appear more legible.

However, typographic opinions are typically anecdotal with no basis in evidence. "Opinions are not always safe guides to legibility of print", and when direct studies are conducted, anecdotal opinions—even those of experts—can turn out to be false. Text that seems legible (visually pleasing at first glance), may be shown to actually impair reading effectiveness when subjected to scientific study.

Studies
Direct studies on sentence spacing include those by Loh, Branch, Shewanown, and Ali (2002), Clinton, Branch, Holschuh, and Shewanown (2003) and Ni, Branch and Chen (2004) with results favoring neither single, double, nor triple spacing. The 2002 study tested participants' reading speed for single and double sentence spaced passages of on-screen text. The authors stated that "the 'double space group' consistently took longer time to finish than the 'single space' group", but concluded that "there was not enough evidence to suggest that a significant difference exists". The 2003 and 2004 studies analyzed on-screen single, double, and triple spacing. In both cases, the authors stated that there was insufficient evidence to draw a conclusion. Ni, Branch, Chen, and Clinton conducted a similar study in 2009 using identical spacing variables. The authors concluded that the "results provided insufficient evidence that time and comprehension differ significantly among different conditions of spacing between sentences".