Mora | Japanese with Anime

In Japanese, one mora is the length of time it usually takes to pronounce one kana 仮名, although there are exceptions.

Grammar

Basically every kana takes one mora of time to pronounce. Consequently, a word spelled with four kana should take twice as long to pronounce a word spelled with two kana. For example:

na-ru
なる
To become.
- This takes two mora.
na-ri-ma-su
なります
To become. (polite form.)
- This takes four mora.

How long absolutely a word takes to pronounce varies. If you speak very fast, obviously it's going to take less time, while if you speak very slowly, it will take more time. But none of this matters.

The mora is a unit used to distinguish a short syllable, which takes one mora, from a long syllable, which takes two moras.

It doesn't matter the speed in which you pronounce the word. If you pronounce a short syllable in 300ms, then 300ms is the mora. If you pronounce the short syllable in 1 second, then 1 second is the mora.

The point is that if you pronounce the word at consistent speed, the long syllable should take 600ms and 2 seconds respectively, or two moras.

Rules

In Japanese, all fifty syllables represented by a single kana take one mora to pronounce.

hi-ya-ke
ひやけ
日焼け
Sunburn. Tan.
- Three mora.

The hiragana and katakana are said to be syllabaries, as each kana represents a whole syllable. This might mislead you to think that each mora is a syllable. For example, in hiyake we have three mora and three syllables. However, mora and syllables are different things.

Furthermore, kana and syllables are also different things.

Diphthongs, which are syllables that combine two vowels, represented by compound kana composed of two characters—one normal kana plus one small kana—also take only one mora to pronounce, as opposed to two.

hya-ku
ひゃく
百
One hundred.
- Two mora, two syllables, three kana.

The nasal vowel n ん takes one mora to pronounce, but doesn't create a new syllable.

ja-n-ke-n
じゃんけん
Rock-paper-scissors.
- Four mora, two syllables, five kana.

The small tsu っ, which represents a geminate consonant, takes one mora to pronounce, but doesn't create a new syllable.

ke-k-ka
けっか
結果
Result.
- Three mora, two syllables, three kana.

Long vowels, which include ~ei and ~ou endings, among others, take twice as long to pronounce, but do not create new syllables. Such long vowels can also be represented by the ー prolonged sound mark.

ta-ma-shi-i
たましい
たましー
魂
Soul.
- Four mora, three syllables.
to-ke-i
とけい
とけー
時計
Clock.
- Three mora, two syllables.
se-n-se-i
せんせい
せんせー
先生
Teacher.
- Four mora, two syllables.
ga-k-ko-u
がっこう
がっこー
学校
School.
- Four mora, two syllables.
o-jo-u-sa-ma
おじょうさま
おじょーさま
お嬢様
Daughter.
Young lady.
Rich girl.
- Five mora, four syllables.

Syllabeme Dialects

Certain Japanese dialects, termed "Syllabeme Dialects," Shirabiimu Hougen シラビーム方言, aren't based on mora, but on syllables, instead.

In such dialects, long vowels, the nasal vowel n ん, the small tsu っ, and even diphthongs such as ~ai and ~oi, can't be divided into separate units.^{(松木, 2011:121)}

For example, in standard Japanese, used in Tokyo, and in most anime, words are measured based on mora. This means that a word like taigai 大概, "generally," can be spelled out loud as ta-i-ga-i たいがい. Each kana, mora, can be isolated.

In the Kagoshima dialect, the spelling is the same: taigai たいがい, but it's pronounced tege てげ.

Since it's pronounced tege てげ, if you spelled out loud ta-i-ga-i たいがい, separately, people wouldn't know what word you're trying to spell, because the vowels ~a-i of the diphthong syllables tai and gai were merged into ~e in this dialect.

Consequently, in such syllabeme dialects, one kana doesn't equal one mora anymore. The thing is closer to English, in which even a long word full of letters like "queue" only has one syllable.

According to Shibata^{(1962, as cited in 松木, 2011:119)}, the syllabeme dialects are found in the following regions of Japan:

Touhoku
東北
Hokuriku
北陸
Miyazaki
宮崎
Kagoshima
鹿児島
Nantou
南東

Such dialects may also feature other differences from standard Japanese. For example, in the Touhoku dialect, the yotsugana 四つ仮名 ji-di-zu-dzu じぢずづ are all pronounced the same way.

In Poetry

In Japanese poetry, poems are sometimes classified according to how many moras each line has. For example:

haiku
俳句
5-7-5.
tanka
短歌
5-7-5-7-7.

Observe below:

5: chi-ha-ya bu-ru
ちはやぶる
千早振る
Turbulently.
7: ka-mi-yo mo ki-ka-zu
かみよもきかず
神代も聞かず
Even in the divine age unheard.
5: Ta-tsu-ta-ga-wa
たつたがわ
竜田川
The Tatsuya river.
7: ka-ra ku-re-na-i ni
からくれなゐに
唐紅に
To crimson.
7: mi-zu ku-ku-ru to-wa
みずくくるとは
水括るとは
The water dyed.
In the anime Chihayafuru, character Kanade interprets this poem as being about love. Generally the crimson-dyed water is interpreted as being red autumn leaves covering the river. Personally, I can't really tell what it's supposed to mean. I'm not good with poems.