Consonant mutation

From Academic Kids

de:Anlautmutation fr:Mutation_consonantique zh:子音變化

Consonant mutation is the phenomenon in which a consonant in a word is changed according to its morphological and/or syntactic environment.

Mutation phenomena are found in languages around the world. The prototypical example of consonant mutation is the initial consonant mutation of all modern Celtic languages. Initial consonant mutation is found also in Japanese, Indonesian or Malay, in Southern Paiute and in several West African languages such as Fula. Baltic Finnic languages such as Finnish and Estonian have mutation of word-internal consonants. The Nilotic language Dholuo, spoken in Kenya, shows mutation of stem-final consonants, as does English to a small extent. Mutation of initial, medial, and final consonants is found in Modern Hebrew.



For details see the articles on the individual languages: Breton language, Cornish language, Irish initial mutations, Manx language, Scottish Gaelic language, Welsh language.

The Celtic languages are well known for their initial consonant mutations. The individual languages vary on the number of mutations available: Scottish Gaelic and Manx have one, Irish has two, and the Brythonic languages Welsh, Breton and Cornish each have three (but not the same three). Additionally, Irish and the Brythonic languages have so-called "mixed mutations", where a trigger will cause one mutation to some sounds and another to other sounds. The languages vary on the environments for the mutations, though some generalizations can be made. In all the languages, feminine singular nouns are mutated after the definite article, and adjectives are mutated after feminine singular nouns. In most languages, the possessive pronouns trigger various mutations. Some examples from Breton, Irish and Welsh:

Breton Irish Welsh Gloss
maouez bean gwraig woman
bras mr mawr big
ar vaouez vras an bhean mhr y wraig fawr the big woman
kazh cat cath cat
e gazh a chat ei gath his cat
he c'hazh a cat ei chath her cat
o c'hazh a gcat eu cath their cat


Rendaku (meaning sequential voicing) is a mutation of the initial consonant of a non-initial component in a Japanese compound word. Some compounds exhibiting rendaku:
nigiri + sushi → nigirizushi ("squeeze" + "sushi" → "hand-shaped sushi")
nigori + sake → nigorizake ("muddy" + "rice wine" → "unfiltered sake")

Nigori in "nigorizake" and the daku in "rendaku" are actually different readings of the same kanji 濁, because voiced and unvoiced consonants are described in Japanese as opaque and clear.


The active form of a multisyllabic verb with an initial stop consonant or fricative consonant is formed by prefixing the verb stem with me- and a nasal consonant with the same place of articulation as the initial consonant.

  • garuk → menggaruk (= to scratch), hitung → menghitung (= to count),
  • beri → memberi (= to give), fitnah → memfitnah (= to falsely accuse),
  • cari → mencari (= to search), dapat → mendapat (= to obtain), *jangkau → menjangkau (= to reach)

If the initial consonant is a unvoiced stop or s, it disappears, leaving only the nasal in its place.

  • kandung → mengandung (= to contain or to be pregnant),
  • putih → memutih (= to turn white),
  • satu → menyatu (= to become one / to unite),
  • tulis → menulis (= to write).

Applied to verbs starting with a vowel, the nasal consonant is realized as ng ([ŋ]). Monosyllabic verbs add an epenthetic vowel before prefixing, producing the prefix menge-.

  • bor (= boring tool / drill) → mengebor (= to make a hole with drill).

Verbs starting with a nasal or approximant consonant do not add the mutant nasal at all, just me-.

Examples adapted from Wikibooks:Indonesian_prefix_me (

Southern Paiute

In Southern Paiute, there are three consonant mutations, which are triggered by different word-stems. The mutations are Spirantization, Geminatation, and Prenasalization:

Radical Spirantization Gemination Prenasalization
p v pp mp
t r tt nt
k kk ŋk
kw w kkw ŋkw
ts   tts nts
s   ss  
m ŋkw mm mm
n   nn nn

For example, the absolutive suffix -pi appears in different forms, according to which noun stem it is suffixed to:

  • movi-ppi 'nose'
  • sappI-vi 'belly'
  • aŋo-mpi 'tongue'


The Gombe dialect of Fula, spoken in Nigeria, shows mutation triggered by declension class. The mutation grades are Fortition and Prenasalization:

Radical Fortition Prenasalization
f p p
h k k
w b mb
r d nd
j , g , ŋg
g ŋg

For example, the stems rim-' 'free man' and ' 'person' have the following forms:

  • (class 2), dimo (class 1), ndimon (class 6)
  • (class 2), gimɗo (class 1), ŋgimkon (class 6)


In Finnish (and related languages such as Estonian), stem-medial consonants undergo mutation (usually called gradation in the literature). One of the mutations is known as weakening; here is a partial list:

Radical Weakened
pp p
tt t
kk k
p v
t d
k hiatus
mp mm
nt nn
nk ng
lt ll
rt rr
uku/yky uvu/yvy

For example, nouns and adjectives in the genitive singular generally have weakened versions of stem-medial consonants:

  • lappu 'piece of paper' (nom.), lapun (gen.)
  • halpa 'cheap' (nom.), halvan (gen.)
  • kota 'Lappish tent' (nom.), kodan (gen.)
  • suka 'brush' (nom.), suan (gen.)
  • puku "a suit", puvun (gen.)

For a more complete list, see [1] (

Sandhi effects often cause word-final consonant mutations in speech, but this is not spelled out in standard language.


The Dholuo language (also named as the Luo language) shows alternations between voiced and voiceless states of the final consonant of a noun stem. In the construct state (the form that means 'hill of', 'stick of', etc.) the voicing of the final consonant is switched from the absolute state. (There are also often vowel alternations that are independent of consonant mutation.)

  • 'hill' (abs.), god (const.)
  • 'stick' (abs.), luð (const.)
  • 'appearance' (abs.), kit (const.)
  • 'bone' (abs.), (const.)
  • buk 'book' (abs.), bug (const.)
  • 'book' (abs.), (const.)


English has a no longer productive process of voicing stem-final fricatives, which is encountered both in noun-verb pairs and in the formation of plural nouns.

  • belief - believe
  • life - live
  • proof - prove
  • strife - strive
  • thief - thieve
  • ba - bae
  • brea - breae
  • mou (n.) - mou (vb.)
  • shea - sheae
  • wrea - wreae
  • choie - chooe
  • houe (n.) - houe (vb.)
  • ue (n.) - ue (vb.)

The voicing alternation found in plural formation is losing ground in the modern language, and of the alternations listed below many speakers retain only the [f-v] pattern, which is supported by the orthography.

  • knife - knives
  • leaf - leaves
  • self - selves
  • shelf - shelves
  • wharf - wharves
  • wife - wives
  • wolf - wolves
  • ba - bas
  • mou - mous
  • oa - oas
  • pa - pas
  • you - yous
  • houe - houes

Modern Hebrew

Modern Hebrew shows a limited set of mutation alternations, involving spirantization only. The consonants affected may be stem-initial, stem-medial, or stem-final.

Radical Spirantized
p f
k x
b v

For example, some verbs show mutation between tenses and conjugation classes:

  • katav 'he wrote', yixtov 'he will write'
  • tiba 'he sank' (intransitive), tava 'he sank' (transitive)

Some nouns show mutation between masculine and feminine, between singular and plural, or after prepositions:

  • melex 'a king', malka 'a queen'
  • dov 'a bear', dubim 'bears'
  • bayit 'a house', be-vayit 'in a house'

But not all words have alternations:

  • xatav 'he hacked', yaxtav 'he will hack'
  • zikef 'he put up', zakaf 'he raised'
  • tov 'good', tuvim 'goods'
  • kibuc 'a kibbutz', be-kibuc 'in a kibbutz'


The Sindarin language created by J. R. R. Tolkien has mutation patterns inspired by those of Welsh. The first letter of a noun usually undergoes mutation when the noun follows a closely associated word such as an article or preposition. Thus, we get certh, rune, and i gerth, the rune. Also, second elements of compounds and direct objects of verbs undergo mutation.

Mutation vs. sandhi

Initial consonant mutation must not be confused with sandhi, which can refer to word-initial alternations triggered by their phonological environment, unlike mutations, which are triggered by their morphosyntactic environment. Some examples of word-initial sandhi are listed below.

  • Spanish: [b, d, g], occurring after nasal consonants and pause, alternate with , occurring after vowels and liquid consonants. Example: un [b]arco 'a boat', mi [β]arco 'my boat'.
  • Scottish Gaelic: stops in stressed syllables are voiced after nasals, e.g. [khaht] 'a cat', ghaht] 'the cat'.
  • Nivkh: stops become fricatives after vowels, and fricatives become stops after other fricatives. Examples:
    • 'neck', 'neck of a reindeer'
    • 'shoot', 'to shoot a bear'

Sandhi effects like these (or other phonological processes) are usually the historical origin of morphosyntactically triggered mutation. For example, the English fricative mutation described above originates in an allophonic alternation of Old English, where a voiced fricative occurred between vowels (or other voiced consonants), and a voiceless one occurred initially or finally, and also when adjacent to voiceless consonants. Old English infinitives ended in -(i)an and plural nouns (of one very common declension class) ended in -as. Thus, hūs 'a house' had , while hūsas 'houses' and hūsian 'to house' had . After most endings were lost in English, and the contrast between voiced and voiceless fricatives phonemicized (largely due to the influx of French loanwords), the alternation was morphologized.


  • Arnott, D. W. The Nominal and Verbal Systems of Fula. Oxford: Oxford University Press, 1970.
  • Blevins, Juliette. "Gilyak lenition as a phonological rule." Australian Journal of Linguistics 13 (1993): 1–21
  • Branch, Michael. "Finnish." In The World's Major Languages, edited by Bernard Comrie, 593-617. Oxford: Oxford University Press, 1987.
  • Fife, James, and Gareth King. "Celtic (Indo-European)." In The Handbook of Morphology, edited by Andrew Spencer and Arnold M. Zwicky, 477–99. Oxford: Blackwell, 1998.
  • Glinert, L. The Grammar of Modern Hebrew. Cambridge: Cambridge University Press, 1989.
  • Gruzdeva, Ekaterina. "Aspects of Nivkh morphophonology: initial consonant alternation after sonants." Journal de la Socit Finno-Ougrienne 87 (1997): 79–96.
  • Sapir, Edward. "The Southern Paiute Language (Part I): Southern Paiute, a Shoshonean Language." Proceedings of the American Academy of Arts and Sciences 65 (1930): 1–296.

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