Mnemonic major system

The major system (also called the phonetic number system, phonetic mnemonic system, or Herigone's mnemonic system) is a mnemonic technique used to aid in memorizing numbers.

The system works by converting numbers into consonant sounds, then into words by adding vowels. The system works on the principle that images can be remembered more easily than numbers.

Each numeral is associated with one or more consonants. Vowels and the consonants w, h, and y are ignored. These can be used as "fillers" to make sensible words from the resulting consonant sequences. A standard mapping is:

The groups of similar sounds and the rules for applying the mappings are almost always fixed, but other hooks and mappings can be used as long as the person using the system can remember them and apply them consistently.

Each numeral maps to a set of similar sounds with similar mouth and tongue positions. The link is phonetic, that is to say, it is the consonant sounds that matter, not the spelling. Therefore, a word like action would encode the number 762 (/k/-/ʃ/-/n/), not 712 (k-t-n). Double letters are disregarded when not pronounced separately, e.g. muddy encodes 31 (/m/-/d/), not 311, but midday encodes 311 (/m/-/d/-/d/) while accept encodes 7091 (/k/-/s/-/p/-/t/) since the ds and cs are pronounced separately. x encodes 70 when pronounced as /ks/ or /gz/ (e.g. in fax and exam) and 76 when pronounced /kʃ/ or /gʒ/ (e.g. in action or luxury); z encodes 10 when pronounced /ts/ (e.g. in pizza). In ghost (701, /g/-/s/-/t/) and enough (28, /n/-/f/), gh is being encoded by different numerals. Usually, a rhotic accent is assumed, e.g. fear would encode 84 (/f/-/r/) rather than 8 (/f/).

Often the mapping is compact. Hindquarters, for example, translates unambiguously to 2174140 (/n/-/d/-/k/-/r/-/t/-/r/-/z/), which amounts to seven digits encoded by eight letters, and can be easily visualized.

Each numeral maps to a set of similar sounds with similar mouth and tongue positions. For most people it would be easier to remember 3.1415927 (an approximation of the mathematical constant pi) as:

Short term visual memory of imagined scenes allows large numbers of digits to be memorized with ease, though usually only for a short time.

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