EkaPad chords are optimized for American English

Some design considerations in the selection of chords for the EkaPad.

EkaPad can produce all characters in the Mac OS and the Windows OS in multiple languages.

Note: The word character in EkaPad documents means a letter (abc...xyz), a numeral (123...890), a punctuation mark (;:,.}), a symbol (# ...@), a command (cntrl, shift, alt), a state chord (GridPad, Navig), an EkaPad prefix (Caps, Post, 3Post), or a special EkaPad process (10-ones, KeepAccess).

Letters, punctuation, and numerals, have chords chosen by their frequency, with the most frequent having easy one or two finger chords and the less frequent having two and three finger chords. Some other characters were given simple chords because the characters were familiar to qwerty keyboard users. Others because they are used often with a computer. Still others are placed so the user needs only remember one or two things to get the right chord sequence for a character, for instance, PostCaps then r for ®, c for ©, t for ™. Most users need only learn a few special chords for their own work.

In selecting the characters and chord placement, the designs of the qwerty keyboard, the telephone keypad, and some musical instruments played a part, often an important but a small part.

What must be taken into account when selecting chords is both the ease of making the chord and the location of the chord both on the keypad and with its relation to its neighbors. If there are any common or acceptable mnemonics relating two or more characters to each other, then chords which could be related were chosen.

Lists of common words and common letters are useful. However it is also important to consider the frequency of occurrence as a number (usually as a percent). Otherwise, knowing the letter z is the least common letter in English may lead one to think it occurs 1/26th of the time or with a frequency of about 4%, when in fact the frequency of z is 0.09%. The letter z occurs only once in every 1,000 letters in English, whereas the letter e has a frequency of 10%, or once every 10 letters.

Letter and word frequency data developed by EkaTetra

In developing frequency tables, we started with data from other sources. We also wanted some hard numbers, so we created a half million character document from current diverse sources and found the character frequencies within the document. These frequencies were close enough to other ones we, and others, had extracted that we stuck with these frequencies. Using this approach we have hard numbers rather than just an ordered list.

LF_HalfMillionFrequencies.pdf This document shows the single letter frequencies we derived.

LF_121MostCommonWords_LetterFreq.pdf This document contains a list of the most common words in American English as found by two scholarly works. We have added the frequencies of all the letters in the list. The first 100 are said to make up about half of all written material. The least frequent of the words occurs more than 2.0% of the time.

LF_Report_Chords_LetterFrequencyAnalysis.pdf This is quite an extensive report on the EkaPad chords and their frequencies. Chords icons for single letters and all common digrams (2 letter sequences like er) are shown along with their frequencies.

EkaPad_Alphabet.pdf Chord icons for the alphabet.

LF_Common_LettersWords.pdf More data on letter and word frequencies from another.

Revised 18 August 2009