With 3-digit number systems becoming more prevalent among mnemonists today, 4-digit number systems have become the new frontier for finding possible increases in number memorization speed and retention. The addition of 10,000 images for a 4-digit system presents a daunting proposition. For most people, a 2-digit system will amply suffice for remembering 4-digit numbers. A 3-digit number system is recommendable to a serious mnemonist, but a 4-digit system is only known to have been attempted by a few.
If the sole purpose of learning a 4-digit system is to remember numbers, it may be considered too great a time investment. But when the same system can be used to mentally catalog the precise sounds of English words and names, as well as playing cards and binary number combinations if so desired, it becomes considerably more valuable.
This system provides a framework for the mnemonist and linguist alike to pronounce every one of the 11,110 different combinations of numbers from 1 to 4 digits in length, in a single syllable. It is an expansion on the principles of the Major System for number-consonant conversion, the work of Ben Pridmore and his use of fixed-vowel assignments (see Ben System), and the ideas of Josh Cohen that such systems can be used for linguistical purposes.
Every 1 and 2-digit number is assigned a unique phoneme or sound of the English language. These sounds, comprised of vowels, consonants, and consonant blends, are phonetic building blocks for pronouncing 3 and 4-digit numbers. Many of the vowel and consonant assignments will be intuitive to a person already familiar with the Major System. Consonant blends are listed in alphabetical order within their respective sections (Initial Blends, Final Blends, and Other Sounds) and must simply be memorized. The “Other Sounds” of numbers 50-69 are not used elsewhere in the system, but are still of use for language purposes, as discussed later.
The system is designed to incorporate as many syllables of the English language as possible, and by nature will include many non-English syllables as well. As such the system cannot be termed as simple, but every effort has been made to simplify the system where possible. Logical sectioning of the system key and many repeating sequences should greatly aid in learning of the system so that it can be put into practice as soon as possible.
This system has been designed from an American English perspective. Pronunciations used in the system key are based on the Wikipedia pronunciation respelling key. Examples of the pronunciations and their IPA equivalents can be found there.
Vowels are assigned to the 1-digit numbers based on the Major System’s predominant approach of matching letter shapes with number shapes. This method encourages the reader to visualize the numbers as letters, and thereby facilitates phonetic reading of the numbers.
To understand vowel assignments, it is necessary to consider how numbers are commonly substituted for vowels in English-speaking cultures, such as on license plates and the internet (see Leet). The number 3, for example, bears strong resemblance to the letter E, and thus is commonly substituted for the letter E. When placed between two consonants, the letter E generally makes the “eh” sound.
The chosen vowel assignments conveniently coincide with an overall phonetic division of two parts: Numbers 0 through 4 can be visualized as capital letters with short vowel sounds. 5 through 9 can be visualized as lower-case letters, sometimes with a macron (horizontal line) above them, and are long vowel sounds.
0 “ah” /ɑː/ The 0 undoubtedly resembles a capital O, and is commonly substituted for an O in popular culture. Between two consonants, an O generally makes an “ah” sound as in “H0T” or “T0P”. Closely-related “ah” or “aw” vowel sounds are merged into this vowel, see cot-caught merger.
1 “ih” /ɪ/ The 1, characteristically defined by its single vertical line, and sometimes accompanied by a serif at the top and horizontal line at the bottom, looks much like the capital letter I, and for this reason is commonly substituted for the letter I in popular culture. Between two consonants, an I will usually make an “ih” sound like in “B1D” or “G1N”.
2 “uh” /ʌ/ The 2, when turned 90 degrees clockwise, resembles a U, much like the way the number 2 can be rotated counter-clockwise to resemble the letter n in the Major System. Found between two consonants, a U often makes the “uh” sound as in “F2N” or “N2T”.
3 “eh” /ɛ/ The number 3 is nearly identical to the capital letter E when flipped on its vertical axis. In English, an E between two consonants will generally make the “eh” sound as in “M3N” or “Y3T”.
4 “a” /æ/ The 4 bears strong resemblance to a capital letter A. When placed between two consonants, the A will make the “a” (æ) sound as in “C4T” or “S4M”.
5 “oh” /oʊ/ The 5 assignment may be the most imaginative of the vowel assignments in this system, but can be readily seen by mentally shifting the 5’s vertical line downward to close the open circle. The result is a lower-case o with a macron above it (ō), which is how English dictionaries often denote the long “oh” sound as in “h5me” or “p5le”.
6 “ay” /eɪ/ The number 6, when flipped on its vertical axis, looks strikingly like a lower-case a. The long a (ā) sounds like “ay” as in “g6me” or “r6te”.
7 “eye” /aɪ/ The 7 can be seen as a lower-case i with a macron in place of the dot (ī). The long i sounds like “eye” as in “t7re” or “k7te”. A 7 can alternatively be visualized as the two strokes of a y, which can also make the long i sound.
8 “oo” /uː/ The number 8, when turned sideways, looks very much like two o’s side-by-side. Naturally this would correspond with the English “oo” (ōō, see The American Heritage Dictionary pronunciation key) sound as in “b8t” or “s8n”.
9 “ee” /iː/ Like the 3 and the 6, the number 9 needs only to be flipped on its vertical axis to look very much like a lower-case e. The long e (ē) sounds like “ee”, such as in “m9te” or sc9ne”.
The r sound after a vowel modifies the vowel’s pronunciation. To adjust for this change, an italicized set of alternate sounds is found in the vowels section. The alternate pronunciations for numbers 3-9 account for most English r-controlled vowel sounds. The remaining three alternate pronunciations, “ow” as in cow, “oy” as in toy, and “uu” as in book, are placed in this section as a means for the system to accommodate English syllables which may include these common sounds.
Note that the specific sounds of the italicized set are assigned to numbers in the 500s ending with 4. E.g. 504 “ow”, 514 “oy”, 524 “uu”, etc.
The twenty most common English consonant sounds are divided in the system into two classes. The primary class, assigned to 00-09, are the consonant sounds most strongly associated with their assigned numbers in the Major System. This is usually the first listed sound next to a number in most versions of the Major System, and generally coincides with a similarity of the letter to the number shape. Resources specific to the Major System can be consulted for further understanding on these assignments. The secondary class of consonant sounds, assigned to 10-19, include many of the alternate sounds for each number in the Major System, as well as some additional sounds.
The primary class of consonants are the same whether they are at the beginning or end of a syllable. The secondary class of consonants contain two letters, h and w, which are more useful in the system as initial consonant sounds than final consonant sounds. For this reason, h and w are replaced by ng (as in “ha”) and zh (as in “meaure”) when ending a syllable.
The breadth of a 4-digit system allows for inclusion of many initial and final consonant blends commonly found in the English language. For the sake of simplicity these blends are assigned within their section in alphabetical order. Attempt has been made to place the most frequent of these sounds in the Initial Blends and Final Blends sections, leaving the Other Finals section to include any extras.
For as many available combinations of numbers as there are in this system, there is still not enough room to accommodate every type of consonant blend without vastly increasing complexity. Because of this, final blends are omitted from the 4-digit section of the system key. Since it may generally be more important in the recall of words and names to know the first part of a syllable’s sound, preference is given to the initial consonant blends in the 4-digit section.
Artificial Language and Code
The idea of converting words into arrangements of non-standard symbols has been around for millennia. Applying this principle to mnemonic number systems has been discussed by Josh Cohen and again recently by Dale Oliver.
For purposes of remembering actual words or names, for additional practice, or for mere enjoyment, this system can be used as an artificial language or code for English with a high degree of precision. The pronunciation of any English word can be closely approximated, if not wholly replicated, by a short series of numbers. In addition to the spaces and punctuation marks already used in the English language, only a single symbol is needed to clarify the separation of sounds within words. The inobtrusive apostrophe (‘) may be well-suited for this purpose.
Hello, how are you today?
1235’5, 1204 544 498 5181’6?
Cards and Binaries
A 4-digit system can easily be adapted for other memorization interests such as for remembering the order of playing cards or strings of binary numbers. For example, a 1-card system can be made by assigning an existing 2-digit number image to each of the 52 playing cards. A 2-card system can be made by assigning existing 4-digit number images, corresponding to two 2-digit numbers side-by-side, to each of the 2,704 different 2-card combinations. A similar system of reusing 4-digit number images can be devised for combinations of ones and zeros. Anyone particularly interested in these disciplines is welcome to contribute ideas on how to best adapt the system for these uses.
Considering the large scale of this system, it seems prudent for the user to expend the least possible amount of effort in selecting images to correspond with each number. At the same time, it would be senseless to assign random images to all the number combinations when many of them, by virtue of their particular pronunciation, will invoke a particular image in the user’s mind.
To speed up image selection, the user can be presented with a list of possible word candidates for each number. This can be accomplished programmatically using phonetic dictionary resources like the Carnegie Mellon University (CMU) Pronouncing Dictionary. As stated on their site, the CMU dictionary “is an open-source machine-readable pronunciation dictionary for North American English that contains over 134,000 words and their pronunciations”. It uses 39 phonemes based on ARPABET pronunciation to convert English words into their corresponding sounds in General American English.
Thanks to Mnemoriam, a word-generating program for the system is now available! A user can enter any number from 1 to 4 digits in length and see possible matches from the CMU dictionary. See section on Word Generator below.
When all user-defined or script-suggested image selections have been exhausted, it may then be necessary to assign random images to the remaining numbers. This is, of course, the last resort, but needful to complete the system assignment phase in a timely manner so the user can move on to memorization and fluency of system images.
Mnemoriam has generously created a script for automatically generating words that match the pronunciation of numbers in the system.
Here are instructions for running the program on Windows computers:
- Install Python 3.
- Download the .py and .txt files from this link
- Create a convenient folder on your local drive such as
C:\slateand put the .py and .txt files in that folder.
- Go to the Start menu and type
cmd [Enter]to launch the Command Prompt.
- In the Command Prompt type
cd C:\slate [Enter]or similar, according to the name of the folder you created, to change directory to that folder.
python [Enter]to launch Python at that directory within the Command Prompt. If you don't see the current version number of your installed Python, then you may need to perform a web search on how to add Python as a PATH Environment Variable on your system.
import slate [Enter]
slate.convert("3961") [Enter]and you should see ['S', 'L', 'EY', 'T'] with matching words. Modify the number in quotations to search for other numbers.
- To modify the standard limit of 30 words, use a comma followed by the desired number within the parenthesis. E.g.
slate.convert("0",100)will give one hundred matches for the "ah" sound of the number zero.
The system is now complete and no longer under revision. Enjoy!