What is a Long Vowel?

A long vowel (長母音, chōboin) in Japanese is a sound where a vowel is stretched for an extra beat, like かあさん (kaasan, mother), it can be also “かーさん”(kāsan). 

Examples:

• かあさん (kaasan, mother) → かーさん(kāsan)

• ばあさん (obaasan, grandmother) → おばーさん（bāsan)

　• にいさん (niisan, older brother) → にーさん(nīsan)

• おじいさん (ojiisan, grandfather) → おじーさん(ojīsan)

• くうき (kuuki, air) → くーき(kūki)

• ふうふ (fuufu, married couple) → ふーふ(fūfu)

• ねえさん (neesan, older sister) → ねーさん(nēsan)

• ええ (ee, yes) → えー(ē)

Exceptions and Special Cases

1. E-row long vowels that use “い” instead of “え”

Some words in the E-row use “い” instead of “え” for long vowels, even though they are pronounced differently:

• せい (背, se, back) → Can be pronounced “セー” (sē) or “セイ” (sei)

• えいが (映画, eiga, movie) → Can be pronounced “エーガ” (ēga) or “エイガ” (eiga)

2. O-row long vowels that use “う”

Words that are pronounced with a long O sound but are written with “う” instead of “お”:

• おとうさん (お父さん, otousan, father) → Pronounced “オトーサン” (otōsan)

• あそぼう (asobou, let’s play) → Pronounced “アソボー” (asobō)

3. Historical Spelling Rules

Some words historically used “ほ” or “を” after an O-row kana, but today they are written with “お” while still pronounced as long vowels.

These words can be pronounced as a true long vowel (オー) or as two separate vowels (オ・オ or コ・オ).

• こおり (氷, kōri, ice) → Pronounced “コーリ” (kōri) or “コオリ” (koori)

• おおやけ (公, ooyake, public) → Pronounced “オーヤケ” (ōyake) or “オオヤケ” (ooyake)

• とおる (通る, tooru, to pass) → Pronounced “トール” (tōru) or “トオル” (tooru)