In
linguistics, a 'consonant cluster' is a group of
consonants which have no intervening
vowel. In English, for example, the groups and are consonant clusters in the word ''splits''.
Some linguists argue that the term can only be properly applied to those consonant clusters that occur within one
syllable. Others contend that consonant clusters are more useful as a definition when they may occur across syllable boundaries. According to the former definition, the longest consonant clusters in the word ''extra'' would be and , whereas the latter allows . The German word ''Angstschweiß'' (cold sweat) is another good example.
Consonant clusters crosslinguistically
Languages'
phonotactics differ as to what consonant clusters they permit.
Many languages do not permit consonant clusters at all.
Maori and
Pirahã, for instance, don't permit any more than one consonant in a row before another vowel must appear.
Japanese is almost as strict, but it allows clusters of consonant plus as in ''Tokyo'', the name of the capital city. Across a syllable boundary, it also allows a cluster of a
nasal consonant plus another consonant, as in ''Honshū'' (the name of the largest island) and ''
tempura''. A great many of the languages of the world are more restrictive than English in terms of consonant clusters; almost every
Malayo-Polynesian language permits either one-term clusters or slight variations on a theme.
Tahitian,
Fijian,
Samoan and
Hawaiian are all of this sort. Standard
Arabic does not permit initial consonant clusters, or more than two consecutive consonants in other positions.
Finnish has initial consonant clusters natively only on South-Western dialects and on foreign loans, and only clusters of three inside the word are allowed. Most spoken languages and dialects, however, are more permissive.
At the other end of the scale, the
Kartvelian languages of Georgia are almost unbelievable in terms of the consonant clusters they permit. Clusters in
Georgian of four, five or six terms are not unusual - for instance, ''brt'q'eli'' (''flat''), ''mc'vrtneli'' (''trainer'') and ''prčkvna'' (''peeling'') - and if grammatical affixes are used, it allows an eight-term cluster: 'gvbrdγvnis' (''he's plucking us''). Consonants cannot appear as syllable nuclei in Georgian, so this syllable is analysed as CCCCCCCCVC. Some
Slavic languages such as
Slovak may manifest formidable numbers of consecutive consonants, such as in the words ''štvrť, žblnknutie'', but the consonants /r/ and /l/ can form syllable nuclei in Slovak, and behave phonologically as vowels in this case. Another notable word is the
Croatian word ''opskrbljivanje'' (supplying) (though note that, like ''nj'', ''lj'' is a single consonant here: ). Some
Salishan languages exhibit long words with no vowels at all, such as the
Nuxálk word '': ''he had had a bunchberry plant''. It is extremely difficult to accurately classify which of these consonants may be acting as the syllable nucleus, and these languages challenge classical notions of exactly what constitutes a
syllable.
Consonant clusters in loanwords
Consonant clusters occurring in
loanwords do not necessarily follow the cluster limits set by the borrowing language's
phonotactics. The
Ubykh language's root ''psta'', a loan from
Adyghe, violates Ubykh's rule of no more than two initial consonants; also, the English words ''sphere'', ''sphinx'',
Greek loans, violate the restraint that two
fricatives may not appear adjacently word-initially.
Consonant clusters in English
In
English, the longest possible initial cluster is three terms, as in ''split''; the longest possible final cluster is four terms, as in ''twelfths'', ''bursts'' and ''strengths''.
However, it is important to distinguish clusters and
digraphs. Clusters are made of two or more consonant ''sounds'', while a digraph is a group of two consonant ''letters'' standing for only one sound. For example, in the word ''ship'', the two letters "s" and "h" together represent the single consonant . Also note a combination digraph and cluster as seen in "lightning" with three terms: <gh> <t> and <n>; or "length": <ng> <th>.
See also
★
English consonant cluster reductions
★
vowel cluster