Terminology

  • Same Finger Bigram (SFB): Pressing two keys with the same finger in conjunction.

  • Same Finger Skipgram (SFS): Pressing two keys with the same finger, but separated by x letters.

  • Disjointed Same Finger Bigram (dSFB): Synonym for SFS. Not used as much anymore.

  • Lateral Stretch Bigram (LSB): A bigram where your hand must stretch laterally, as in using the middle finger following middle column usage on the same hand. An example is be on QWERTY.

  • Alt-fingering: Pressing a key with a different finger than would be typed with traditional touch typing technique.

  • Alternation: Pressing a key with the opposite hand than you typed the last.

  • Roll: Typing two or more keys with the same hand, moving in the same "direction". For example, on QWERTY, sdf would be a roll, but sfd would not.

  • Inward/Outward Roll: A roll which goes in a particular direction. Inward means towards the center of the keyboard, like df on QWERTY. Outward means away from the center, like fd on QWERTY. Many people, but not all, consider inward rolls to be more comfortable than outward rolls.

  • Redirect/Redirection: A one-handed sequence of at least three letters that 'changes directions'. For example, on QWERTY, sfd would be a redirect, but sdf would not.

  • Hand Balance: How much work each hand does for a layout. For example, a 35%:65% hand balance would mean that the left hand types 35% of keys, and the right hand types 65%.

  • Scissor: A vague concept that generally refers to fingers curling or extending in awkward relations to other fingers on the same hand. QWERTY cw and ex are usually considered significant examples of scissors.

  • Half-Scissor Bigram (HSB): A half-scissor is a pattern where one finger needs to stretch or contract to press a key on the top or bottom row and another finger on the same hand stays on the homerow - but the finger that is on the lower of the two rows is either middle or ring. ok, sc, and rd are common examples of half-scissors on QWERTY.

  • Full-Scissor Bigram (FSB): A full-scissor is a pattern where one finger needs to reach to the top row and another finger on the same hand needs to contract to hit the bottom row - but the finger that is on the lower of two rows is either middle or ring. cr, ex, xt are all FSBs on QWERTY.

  • Half-Scissor Skipgram (HSS): Similar to HSB except it is separated by x letters from another finger.

  • Full-Scissor Skipgram (FSS): Similar to FSB except it is separated by x letters from another finger.

  • Lateral Stretch Skipgram (LSS): Similar to LSB except it is separated by x letters from another finger.

  • Onehand (ONE): A onehand is when all three keypresses are pressed on the same hand, and in an order from left to right or right to left. asd, sdf, and fds are all onehands on QWERTY.