QWERTY is the name of the single most common keyboard layout. It derives its name from the first six letters of the layout, as they are pronounceable in every language that uses the layout. All Latin-based languages use some derivative of the QWERTY layout, adapted to that particular languages' needs. For instance, the German keyboard has the "Y" and "Z" keys reversed, as "Z" is a very common letter in German. The resulting QWERTZ layout is still very familiar and usable to those accustomed to the original QWERTY layout. The French AZERTY keyboard layout has three key pairs transposed, which better represents the French usage of the Latin alphabet.
The QWERTY layout was developed by the inventor of the typewriter, Christopher Sholes, who found that his original alphabetical layout caused keys to jam frequently. The solution, he found, was to place the letters of common two-letter key combinations as far away from each other as possible. While popular legend has it that this was to reduce the typing speed of early typists, this in fact sped them up as they could now alternate hands. The key separation prevented jamming not by slowing typists down, rather, by assuring that the head of the key had enough time to evacuate the paper before the next head came. As the heads were likely coming from different directions (due to the separation) they would also not collide on their way to/from the page.
As typewriter technology improved the need for such wide spacing between common letters was reduced, such that new layouts could be designed that better matched English's letter usage. Many researchers, including Sholes himself, proposed new keyboard layouts that were supposed to be more comfortable to use. However, keyboard manufacturers were reluctant to retool their machines for any of the competing new layouts, and no manufacturer wanted to bring to market a typewriter that trained typists could not operate efficiently. Therefore, few of these new layouts saw any success. The only surviving enhanced layout of that era is the Dvorak layout, named after its inventor Dr. August Dvorak. In fact, there are three Dvorak layouts in use today: a standard two-handed layout, and one each for right- and left- handed typing. While no modern machine uses the Dvorak layout as standard, all major computer operating systems have built-in support for Dvorak typing.
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