spacing

Sentence spacing concerns how spaces are inserted between sentences in typeset text and is a matter of typographical convention. Since the introduction of movable-type printing in Europe, various sentence spacing conventions have been used in languages with a Latin alphabet. These include a normal word space (as between the words in a sentence), a single enlarged space, and two full spaces.
Until the 20th century, publishing houses and printers in many countries used additional space between sentences. There were exceptions to this traditional spacing method—some printers used spacing between sentences that was no wider than word spacing. This was French spacing—a term synonymous with single-space sentence spacing until the late 20th century. With the introduction of the typewriter in the late 19th century, typists used two spaces between sentences to mimic the style used by traditional typesetters. While wide sentence spacing was phased out in the printing industry in the mid-20th century, the practice continued on typewriters and later on computers. Perhaps because of this, many modern sources now incorrectly claim that wide spacing was created for the typewriter.
The desired or correct sentence spacing is often debated, but most sources now state that an additional space is not necessary or desirable. From around 1950, single sentence spacing became standard in books, magazines, and newspapers, and 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. However, some sources still state that additional spacing is correct or acceptable. Some people preferred double sentence spacing because that was how they were taught to type. The few direct studies conducted since 2002 have produced inconclusive results as to which convention is more readable.

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