The Sound Changes section allows both Phonological Rule Notation (PRN) and RegEx notation, which are quite different from each other.

PRN was invented by linguists to describe sound changes. It is the notation that looks like m > n / _i, where

  • > means “changes to”
  • / means “in the environment of”
  • _ denotes where the m would be

Thus, m > n / _i means m changes to n before any i. One big advantage of this system is the syntax for doing “in the environment of” is very simple compared to RegEx.

RegEx, on the other hand, was invented by computer programmers for general pattern finding in text, and has nothing specifically to do with linguistics. It is, however, significantly better standardized and bug tested. One problem with PRN it is not officially standardized, and there are occasionally small inconsistencies in the way linguists transcribe some rules. (In fact, doesn't even have an official name; "Phonological Rule Notation" is something we have coined just for this article.)

For this reason, RegEx is the only option for Spelling rules and Illegal combination rules. See full guide to RegEx here. The Sound Changes section uses PRN by default. If you need to use RegEx, write "re " before the rule, eg: re m(?=V) > n


In plain EnglishPhonological notationRegEx
m changes to n in all environmentsm > nm > n
m changes to n at the beginning of a wordm > n / #_^m > n
m changes to n at the end of a wordm > n / _#m$ > n
m changes to n before em > n / _em(?=e) > n
m changes to n after em > n / e_(?<=e)m > n
m or ŋ changes to n before e{m,ŋ} > n / _e[mŋ](?=e) > n
all consonants change to n before eC > n / _e[bdfghjklmnŋpɹstvwzʃʒʧʤθð](?=e) > n
all consonants change to stops before eC > [+stop] / _eRequires individual rules for each consonant
m changes to n before any vowelm > n / _Vm(?=[aeiou]) > n
delete m before em > Ø / _em(?=e) >
m, optionally followed by s, changes to n before em(s) > n / _ems?(?=e) > n
m changes to n before another syllablem > n / _σRequires a complex definition of what a syllable is
m changes to n before syllable boundary*m > n / _%Requires a complex definition of what the syllable boundary is
m changes to n everywhere except before e**m > n / !_em(?!e) > n
m changes to n everywhere except after em > n / !e_(?<!e)m > n

* % differs from σ in that % includes word boundaries, where as σ doesn't.

** Exception rules can also be added to the end of a normal rule, eg: m > n / _e !s_ means m changes n before e, except after s.

Other shorthand symbols

These shorthand symbols work in phonological rules, and anywhere RegEx can be used. However, be aware they are NOT a part of standard RegEx, and some bugs may arise using them in more complex rules.

Shorthand codeCategory
A or C[+affricate]Affricates
B or V[+back]Back vowels
CConsonants
C[+voice]Voiced consonants
C[-voice]Voiceless consonant
C[+alveolar]Alveolar consonants
C[+alveolo-palatal]Alveolo-palatal consonants
C[+bilabial]Bilabial consonants
C[+dental]Dental consonants
C[+flap]Flap/tap consonants
C[+glottal]Glottal consonants
C[+labiodental]Labiodental consonants
C[+post-alveolar]Post-alveolar consonants
C[+retroflex]Retroflex consonants
C[+palatal]Palatal consonants
C[+pharyngeal]Pharyngeal consonants
C[+trill]Trill consonants
DAny diacritic
ᴅ (small capital D)Any combining diacritic
ᴰ (superscript D)Any non-combining diacritic (eg, aspiration)
E or V[+front]Front vowels
F or C[+fricative]Fricatives
H or C[+laryngeal]Laryngeals
K or C[+velar]Velars
L or C[+liquid]Liquids
MDiphthongs
N or C[+nasal]Nasal consonants
OObstruent
P or C[+labial]Labials
Q or C[+uvular]Uvulars
RSonorant/resonant
S or C[+stop]Stops
U or σSyllable
VVowels, including diphthongs
V[+high]High vowels
V[+low]Low vowels
V[+round]Rounded vowels
V[-round]Unrounded vowels
WSemivowels
XAny phoneme
ZContinuant

Note: In the “changes to” section (between > and / symbols), the uppercase letter is redundant, thus both C[+stop] > [+nasal] / _# and C[+stop] > C[+nasal] / _# are valid rules.