Moras

A mora (plural moras or morae) is a unit of phonological timing used to measure syllable weight and describe rhythm in many languages. It is a foundational concept in moraic theory, a framework for modeling prosody. Moras help account for perceived length differences among syllables and influence timing, vowel length, and consonant timing in speech and poetry.

In prosodic typology, languages are often described as mora-timed, syllable-timed, or stress-timed. In mora-timed languages, rhythm is governed by the number of moras in utterances rather than the count of syllables. Japanese is commonly cited as mora-timed, though analyses vary. In syllable-timed languages, such as Spanish or Italian, each syllable tends to take roughly the same amount of time, so rhythm depends less on mora count.

Counting moras: a short vowel with no final consonant (an open syllable) is typically one mora; a long vowel or diphthong counts as two moras. A syllable with a final consonant (a coda) may add another mora in many theoretical treatments, increasing the syllable’s weight. Different linguistic frameworks may implement mora counting with slight differences.

Applications: Moras are used to describe word structure, define poetic meter, and analyze phonological processes such as vowel length, tempo, and consonant timing. In poetry, forms like haiku are sometimes discussed in mora counts; haiku is frequently described as 5-7-5 morae in Japanese, reflecting timing rather than syllable count.

See also: syllable, syllable-timed language, moraic theory.