Definition:
Vowel length is a phonological feature in which the duration of a vowel sound is contrastive — changing the length of a vowel changes the word’s meaning. Languages that use vowel length as a grammatically significant feature are called vowel-quantity languages.
Vowel Length in Japanese (Critical for Learners)
Japanese is a classic vowel-quantity language. Long vowels are phonemic — confusing them changes the word:
| Short vowel | Meaning | Long vowel | Meaning |
|---|---|---|---|
| obasan | aunt | obaasan | grandmother |
| ojisan | uncle | ojiisan | grandfather |
| kōen (こうえん) | park | different pitch gives different meaning | |
| tōri (とおり) | street | tori (とり) | bird |
In Japanese, long vowels are represented in hiragana by doubling the vowel letter (e.g., aa, ii, uu) or by adding う after /o/ sounds. In romaji, they are marked with a macron (ā, ī, ū, ē, ō).
Mora and Timing
Japanese sound timing is measured in morae: short vowels occupy one mora, long vowels occupy two. Getting vowel length wrong doesn’t just sound foreign — it produces a different word, directly causing misunderstanding.
Vowel Length in Other Languages
- Arabic — Distinguishes short and long vowels (/a/ vs. /aː/); changes grammatical meaning
- Finnish and Estonian — Three-way length distinction in Estonian (short, long, overlong)
- Latin — Vowel length was phonemic and affects poetic meter (dactylic hexameter)
- English — Vowel length exists phonetically (length before voiced consonants) but is not phonemically contrastive in the same way