rhythm
Speech is perceived as a sequence of
events in time, and the word rhythm
is used to refer to the way these events are distributed in time. Obvious examples
of vocal rhythms are chanting as part of games (for example, children calling
words while skipping, or football crowds calling their team's name) or in
connection with work (e.g. sailor's chants used to synchronise the pulling on
an anchor rope). In conversational speech the rhythms are vastly more
complicated, but it is clear that the timing of speech is not random. An
extreme view (though a quite common one) is that English speech has a rhythm
that allows us to divide it up into more or less equal intervals of time called
feet, each of which begins with a stressed syllable: this is called the stress-timed rhythm hypothesis.
Languages where the length of each syllable remains more or less the same as
that of its neighbours whether or not it is stressed are called syllable-timed. Most evidence from the
study of real speech suggests that such rhythms only exist in very careful,
controlled speaking, but it appears from psychological research that listeners'
brains tend to hear timing regularities even where there is little or no
physical regularity.
foot
The foot is a unit of rhythm. It has
been used for a long time in the study of verse metre, where lines may be
divided into sections based on patterns on strong and weak syllables. It is
rather more controversial to suggest that normal speech is also structured in
terms of regularly repeated patterns of syllables, but this is a claim that has
been quite widely accepted for English. The suggested form of the English foot
is that each foot consists of one stressed syllable plus any unstressed
syllables that follow it; the next foot begins when another stressed syllable
is produced. The sentence 'Here is the news at nine o'clock' could be analysed
into feet in the following way (stressed syllables underlined, foot divisions
marked with vertical lines):
|here is the |news at
|nine o |clock
It is
claimed that English feet tend to be of equal length, or isochronous, so that in feet consisting of several syllables there
has to be compression of the syllables in order to maintain the rhythm. There
are many problems with this theory, as one discovers in trying to apply it to
natural conversational speech, but the foot has been adopted as a central part
of metrical phonology.