Timing (linguistics)

Language timing is the rhythmic quality of a particular type of speech, in particular how syllables are distributed across time. One common way of describing language timing is by dividing languages into those with stress timing and those with syllable timing. However, linguists differ on whether this distinction is a good way to describe differences in timing in different languages, and linguists have proposed a wide variety of schemes to try to come up with a workable terminology and set of concepts.

Syllable timing
In a syllable-timed language, every syllable is perceived as taking up roughly the same amount of time, though the absolute length of time depends on the prosody. Syllable-timed languages tend to give syllables approximately equal stress.

Finnish, Slovene, French, Brazilian Portuguese and Spanish are commonly quoted as examples of syllable-timed languages. This type of rhythm was originally metaphorically referred to as 'machine-gun rhythm' because each underlying rhythmical unit is of the same duration, similar to the transient bullet noise of a machine-gun.

Since the 1950s speech scientists have tried to show the existence of equal syllable durations in the acoustic speech signal without success. More recent research claims that the duration of consonantal and vocalic intervals is responsible for syllable-timed perception.

Mora timing
Some languages such as Japanese, Gilbertese or Luganda also have regular pacing, but are mora-timed rather than syllable-timed. In Japanese, a V or CV syllable takes up one timing unit. Japanese does not have long vowels or diphthongs but double vowels, so that CVV takes twice the time as CV. A final /N/ also takes as much time as a CV syllable, and at least in poetry, so does the extra length of a geminate consonant. However, colloquial language is less settled than poetic language, and the rhythm may vary from one region to another, or with time.

Stress timing
In a stress-timed language, syllables may last different amounts of time, but there is perceived to be a fairly constant amount of time (on average) between consecutive stressed syllables. Stress-timing is sometimes called Morse-code rhythm. Stress-timing is strongly related to vowel reduction processes.

English, German, Dutch, Continental Portuguese, Russian, and Czech are typical stress-timed languages, as are some southern dialects of Italian.

Origin of differentiation
This difference comes from the human's two senses of rhythm. When a human hears a fast rhythm, typically faster than 330 milliseconds (ms) per beat, the series of beats is heard as one solid noise. For example, a human can imitate a machine gun sound, but hardly count its beats. Conversely, when a slow rhythm is heard, typically slower than 450 ms per beat, each beat is separately understood. The speed of a slow rhythm can be controlled beat by beat, such as hand clapping in music.

If a language has a simple syllable structure, the difference between the simplest and the most complicated syllables in the language is not wide, and it is possible to say any syllable in less than 330 ms. This includes languages that have very few consonants in each syllable. Thus we can use the fast syllable-timed rhythm. If a language has complex syllables such as ones with consonant clusters, the difference between syllables can be very wide, such as the words I and strengths in English. In this case, the language has slow stress-timed rhythm.