Isochrony is a linguistic analysis or hypothesis assuming that any spoken language's utterances are divisible into equal rhythmic portions of some kind.
[2] However, empirical studies have been unable to directly or fully support the hypothesis, so the concept remains controversial in linguistics.
The idea of was first expressed thus by Kenneth L. Pike in 1945,[6] though the concept of language naturally occurring in chronologically and rhythmically equal measures is found at least as early as 1775 (in Prosodia Rationalis).
[3][9][10][11] However, when viewed as a matter of degree, relative differences in the variability of syllable duration across languages have been found.
Syllable-timed languages tend to give syllables approximately equal prominence and generally lack reduced vowels.
French, Italian, Spanish, Romanian, Brazilian Portuguese, Icelandic, Singlish,[14][15][16] Cantonese, Mandarin Chinese,[17] Armenian,[18] Turkish and Korean[19] are commonly quoted as examples of syllable-timed languages.
More recent research claims that the duration of consonantal and vocalic intervals is responsible for syllable-timed perception.
[29][30] English, Thai, Lao, German, Russian, Danish, Swedish, Norwegian, Faroese, Dutch, European Portuguese,[31][32] and Iranian Persian are typical stress-timed languages.
[34][page needed] Despite the relative simplicity of the classifications above, in the real world languages do not fit quite so easily into such precise categories.
The accents of rural, southern Rio Grande do Sul and the Northeast (especially Bahia) are considered to sound more syllable-timed than the others, while the southeastern dialects such as the mineiro, in central Minas Gerais, the paulistano, of the northern coast and eastern regions of São Paulo, and the fluminense, along Rio de Janeiro, Espírito Santo and eastern Minas Gerais as well the Federal District, are most frequently essentially stress-timed.