A Year in Language, Day 251: Concept: Isochrony and Speech Tempo Isochrony and Speech Tempo are two titles for subtly different takes on the study of the speed at which different languages are spoken. These are not the only such terminology to exist for it, but I felt that between the two most people of any school of thought on this topic would be sated. In brief, languages tend towards two poles of speed; slower languages, who also tend to be more grammatically isolating and have more complex syllable structures, and faster languages, who also tend to be more inflection based (synthetic) and have less complex syllable structure. Some theories place a correlation between phonetic complexity and average word length, which in turn impacts tempo. It works like this: if your language has more restrictions on its syllable structure then the total number of possible syllables is more limited. With a smaller inventory of possible syllables more homophones are inevitable. To avoid having too many homophones words need more syllables to insure distinctiveness. Because words become longer, the language is spoken faster to compensate. It sounds solid, though its shown very difficult to test for. One method of dividing languages by tempo is by what metric they set their tempo. The two main categories here are "syllable-timed" and "stress-timed". The crucial element here is that the languages are timed relative to features of the language itself, thus even though a speaker may speed or slow their speech for any number of social, emotional, or personal reasons, the relative tempo should be consistent. Syllable timed language, as you may be able to guess, give each syllable an equivalent amount of speech time. Spanish, Chinese, and Turkish are all syllable timed. Stress-timed languages instead give an equal amount of time between stressed syllables. This includes English, Russian, and Arabic.
