ATLAS OF LANGUAGE

AT-119-007 · ATLAS 260

Mora

A prosodic unit of weight used by languages to organize the temporal or rhythmic structure of syllables.

Part of the subject path Sound, Phonetics and Phonology

Why is this entry in the Atlas?

A · Analytical concept R1 · Distinct contribution to understanding

Mora separates syllable weight from syllable count and measured duration. It opens comparison of rhythmic systems while requiring language-specific evidence rather than imposing one universal timing grid.

Colours and admission grounds

The rectangular label identifies the entry function: F – linguistic figure or procedure; A – analytical concept; G – foundational concept; E – selected concrete case. The rounded badge indicates the admission ground: R1 – distinctive contribution; R2 – necessary foundation; R3 – justified illustrative case. This editorial rationale explains the current selection rather than claiming an undocumented original selection history.

Explanation

The mora is a prosodic unit of weight used to describe the internal temporal organisation of syllables. Depending on the language, a short open syllable may carry one mora while a long-vowel or closed syllable carries two, with consequences for stress, metre, tone assignment, or phonological processes. A mora is neither simply a letter nor necessarily a fixed amount of physical duration in every language. Its value is relational: segments occupy positions within a weight structure that organises language-specific contrasts. The conceptual movement divides the apparently indivisible syllable into bearers of weight and asks which grammatical patterns respond to their number.

Movement of thought

1. A language displays contrasts in which syllables of similar shape possess different prosodic weight. 2. Analysis assigns one or more moras to vowels and, where appropriate, consonants under language-specific rules. 3. Stress, tone, metre, or phonological alternations are related to the resulting weight structure. 4. A counter-test asks whether the proposed mora explains real patterns or merely renames measured duration. 5. Evidence from several phenomena yields a model of how the language organises time and weight inside the syllable.

Scientific use case

Metrical phonology, linguistic typology, and verse studies use moras to model syllable weight across several phenomena. Acquisition and corpus data can test whether speakers productively treat the proposed weight classes.

Example

In the language under study, a syllable with a long vowel attracts stress while a short open syllable does not. The analysis treats the former as bimoraic and the latter as monomoraic.

Counterexample

An acoustic measurement twice as long does not by itself prove bimoraic structure. If stress, tone, and other processes do not respond to the proposed weight, a purely phonetic account may be preferable.

Distinction

Distinguish the mora from the syllable as a larger prosodic unit, the segment as a sound position, and measured duration as a phonetic value. A mora is an abstract, language-specifically active unit of weight.

Effect on thought and perception

The mora makes hidden differences of syllable weight comparable and connects sound structure with rhythm. Uncritical transfer can, however, force language-specific organisation into a universal grid.

Resonance

The syllable acquires an inner shape of time: not sound alone but distributed weight. Moras are small bearers on which rhythm, tone, and expectation may rest.

Cite this entry

Reich, Michael (Hrsg./ed.): „Mora“. Atlas der Sprache, AT-119-007. ATLAS 260, data model 1.6.0. https://atlasoflanguage.com/concept/AT-119-007

https://atlasoflanguage.com/concept/AT-119-007

The address remains stable; editorial content may evolve. Editorial reading state: 2026-10-15. Include your access date for precise references.

Historical background

The Utrecht reference entry defines the mora through syllable weight and contrasts analyses of short and long vowels. This locates the term in a theoretical account of quantity rather than making it a synonym for syllable or for a fixed number of milliseconds. For the Atlas, the distinction changes what is counted: a syllable may contain more than one weight unit while remaining one syllable. The entry points to works from the 1980s, which are historical leads rather than independently inspected sources in this record. It also does not establish the term’s older metrical history or English borrowing chronology. Further research should connect prosodic measurement with later phonological representation while preserving the difference between an analytical unit and the variable physical duration of an utterance.

How conceptual history changes the analysis

The mora is a prosodic unit of weight, neither a syllable nor a fixed time span; its count must follow phonological structure rather than duration alone.

References for the historical section

  • Utrecht Lexicon of Linguistics, mora, undated reference entry · Moraic theory, syllable weight and listed 1980s references

    Selected witness, not a complete genealogy or first English attestation. Contemporary Atlas comparisons are editorial interpretations. A scholarly reference entry was inspected directly; its references to earlier works are reported secondary leads, not independently inspected historical attestations. Entry publication date is not established.

Historical source evidence and Atlas applications remain separate; this import does not assert new first attestations or a fresh exhaustive source verification.