A Scientific Two-Handed Letter Arrangement

From the mid-1930's to the present, keyboards with a human-factored letter arrangement, known as the "Dvorak," have been produced (Dvorak et al. - U.S. Pat. No. 2,040,248 - May 12, 1936). Dvorak is designed for comfortable touch-typing with maximum efficiency. The letters are scientifically organized to preclude awkward fingering sequences, decrease errors, lessen operator fatigue, and increase typing speed.

The inventors, August Dvorak and William Dealey, analyzed typing behavior to understand how different motions affect headway. They determined that an overlapping succession of two-handed keystrokes is most efficient, and a succession of stabbing one-handed finger taps is ineffective. They invented a keyboard letter scheme that supports a "fluent rhythm of two-handed overlapping keystrokes."

Overlapping keystrokes can only occur when fingering a succession of letters that alternate between the hands. A typist will be actuating a character key with one hand while their other hand is close to connecting with the ensuing character key.

Letters are sequenced in the two-handed Dvorak keyboard with regard for frequency of use and relative finger strengths. High-use letters reside beneath the resting hands. Home-row includes the five basic vowels under the left hand and five of the most frequently used consonants under the right hand. Workloads are aptly distributed between the individual fingers of the two hands.

The efficacy of a keyboard letter arrangement for writing any native language can be readily assessed. The primary factor to be considered is the relative frequency of letter occurrence found in the written language. Do those statistics agree with the ease of reach for the respective letters within the native keymap? To rephrase that... are the high-use letters intentionally placed in the easiest to reach "sweet spots" on the keymap?

In reference to the bottom three rows of a conventional alphanumeric character key array: keys that are positioned in the home-row require the least effort to operate, keys positioned in the top alpha-row require greater effort to operate, and those keys located in the bottom alpha-row require the most exertion.

The following two lines list the percentage of keystrokes per alpha-row for Qwerty vs. Dvorak when typing English.

Qwerty Standard: top alpha-row 52%, home-row 32%, and bottom alpha-row 16% of typing keystrokes.

Dvorak Simplified: top alpha-row 22%, home-row 70%, and bottom alpha-row 8% of typing keystrokes.

It requires less physical effort to operate a Dvorak keyboard. A typist using the Dvorak letter arrangement performs reaches out of home-row at less than half the frequency of a typist using the Qwerty layout.

Although Qwerty and Dvorak were designed for writing English, the foregoing lists of typing keystroke percentages exhibits modest variance when other languages (that use Latin, Greek or Cyrillic scripts) are analyzed.

In the Dvorak keymap, the five basic vowels are placed under the resting left hand across from fifteen consonants assigned to the right hand. Those right-hand consonants are a subset of the more frequently occurring (excluding "Z"). This scheme sets up a comfortable back-and-forth cadence between the hands when building syllables. The "rhythmical flow of typing induced" engenders an increase of writing speed.

In 1944 the U.S. Navy conducted an experiment in which Qwerty typists were retrained on the Dvorak typewriter. That wartime research was inexorably skewed by the participation of the inventor, Lieutenant Commander August Dvorak (Liebowitz and Margolis 1996). The controversial study did produce favorable results, so 2,000 Dvorak machines were requisitioned. Upon review, the U.S. Treasury Department prohibited that acquisition.

In 1945 LCDR Dvorak was contacted by Colonel Robert S. Allen, a U.S. Army combat veteran who lost his right arm in an artillery attack. At the time of his injury Col. Allen was serving on General Patton's staff. Before the war he had made his living working as a newspaper columnist. The writer was not satisfied with his ability to type one-handed on a standard Qwerty machine, so he asked the inventor for help.

Dr. August Dvorak invented an efficient typewriter keyboard letter scheme for the left hand that enabled Col. Allen to return to his prewar profession (Lewis 1946). The inventor complemented that work, creating a Right-handed Dvorak keyboard layout that is fundamentally similar.

The original Dvorak letter arrangement forces a single-hand operator to incessantly make broad side-to-side reaches. The invention of that paradigmatic two-handed letter scheme for typewriter keyboards occasioned an innate obligation to render options for single-hand typists. LCDR Dvorak skillfully discharged that duty.

In 1982 the American National Standards Institute (ANSI) designated the Dvorak Simplified Keyboard letter arrangement as an alternative standard.

Ronald Earl Walker - Simplified Keyboard Historian