The Syllable and the Foot : Summary - Speech Resource Pages

The Syllable and Phonotactic
Constraints
Jonathan Harrington and Felicity Cox
Phonotactic Constraints
We have seen in the preceding section that all languages build their
words from a finite set of phonemic units. It is also true that in all
languages there are constraints on the way in which these
phonemes can be arranged to form syllables. These constraints are
sometimes known as phonotactic or phoneme sequence constraints
and they severely limit the number of syllables that would be
theoretically possible if phonemes could be combined in an
unconstrained way. Some simple examples of phonotactic
constraints in English include: all three-consonant clusters at the
beginning of a word start with /s/ ('sprint', 'squire', 'stew' etc);
nasal consonants cannot occur as the second consonant in wordinitial
consonant clusters unless the first consonant is /s/ (e.g.
there are no words in English than begin with /bm dn/ etc),
although this is certainly possible in other languages (e.g. German
which allows /kn/ in words like 'Knoten', meaning 'knot' - we can
see from the spelling that English used to allow this sequence as
well). Another important point about phonotactic constraints is that
they vary from language to language, as this example of English
and German has just shown.
We will consider firstly why languages have phonotactic constraints.
The main reason is to do with the limits on the talker's ability to
pronounce sequences of sounds as one syllable, and the listener's
perception of how many syllables he or she hears from a given
sequence of phonemes. Consider for example a sequence like /pʁ/
i.e. a voiceless bilabial followed by a voiced uvular fricative. Most of
us with some training can produce this sequence (e.g. /pʁa pʁit/
etc.) as a monosyllabic word even though it doesn't occur in
English. Now try reversing the order of the cluster. With some
phonetics training, you could almost certainly produce /ʁp/, but
what is much harder (even for a trained phonetician) is to produce
the sequence before a vowel such that the resulting sequence is
monosyllabic. For example, try /ʁpi/ -- even your best attempts at
producing the /ʁ/ followed by the /p/ will probably still lead to a
percept of two syllables when /ʁp/ precedes a vowel.