Nouns

In grammar, a noun is a word that refers to a thing, like a "cat." It isn't a verb: "John cats Mary." Or an adjective: "the caty person." Or an adverb: "he spoke catly." It's a noun.

Japanese has nouns too, like neko 猫, which means "cat," and turns out a lot of grammar depends on how nouns work, so that's what I'm going to explain in this article.

Grammar Syntax

Pretty much all grammar syntax involving nouns in Japanese falls into the following patterns:

Adjective + noun.
Noun + particle.
Noun + copula.
Noun + verb.

All adjectives come before nouns in Japanese.

{kawaii} neko
かわいい猫
The cat [that] {is cute}. (i い adjective.)
The cute cat.
{kirei na} neko
綺麗な猫
The cat [that] {is pretty}. (na な adjective.)
The pretty cat.
watashi no neko
私の猫
The cat of me. (no の adjective.)
My cat.
{shaberu} neko
喋る猫
The cat [that] {talks}. (relative clause.)

All particles come after nouns in Japanese.

neko ga shabeta
猫が喋った
The cat spoke. (ga が particle.)
neko wo kau
猫を飼う
To keep-as-a-pet a cat (wo を particle.).
To keep a cat as a pet.
neko ni yatta
猫にやった
To give [it] to the cat. (ni に particle.)

All copulas come after nouns in Japanese.

neko da!
猫だ！
[It] is a cat! (predicative copula.)
{neko na} no ni kawaikunai
猫なのに可愛くない
Even thought [it] {is a cat}, [it] is not cute. (attributive copula.)
{neko ni} natta
猫になった
Became so [it] {is a cat}. (adverbial copula.)
Became a cat.

In some cases, the particle that's supposed to mark a noun isn't explicitly pronounced but can be inferred from context. When this happens, the noun ends up right before the verb.

neko shabetta!
猫喋った
The cat spoke!

Above, we have the same thing as neko ga shabetta without the ga.

Grammatically, such cases are are analyzed as if the noun was marked by an invisible "null particle," represented by ∅, the empty symbol.

Noun Phrases

Noun phrases are nouns formed by multiple words instead of just one.

Most of the time you use a noun in English you're using a noun phrase. For example, "cat" is a noun, but "the cat" is a noun phrase. The word "the" isn't a noun, it's a definite article, a determiner.

Japanese doesn't have articles or plurals like English. A single noun can have various, different translations, including some that are noun phrases rather than single-word nouns.

neko 猫
Cat.
A cat.
The cat.
Cats.
The cats.

Any noun qualified by an adjective counts as a noun phrase. In other words, you have a phrase, and the "head" of that phrase, for grammatical syntax purposes, happens to be a noun, so it's a noun phrase.

{kawaii} neko
かわいい猫
The cat [that] {is cute}.
The cute cat.
- The head of this phrase is "cat," and cat is noun, so it's a noun phrase.

If the head is a noun, it can be used in any place a single-word noun can be used.

{kawaii} neko ga shabetta
かわいい猫が喋った
"The cute cat" spoke.
{kirei na} neko wo kau
綺麗な猫を買う
To keep-as-a-pet "a pretty cat."
{shaberu} neko ni yatta
喋る猫にやった
To give [it] to "the cat [that] {speaks}."
{watashi no neko na} no ni kawaikunai
私の猫なのに可愛くない
Even thought [it] {is "my cat,"} [it] isn't cute.

Compound Nouns

Compound nouns are nouns formed by multiple nouns fused into one. They're different from noun phrases because grammar isn't involved in their creation, they're just two words combined together.

neko 猫
Cat.
mimi 耳
Ears.
nekomimi 猫耳
Cat-ears.

Since they're nouns, they're literally nouns, they work just like nouns. so one would think there's nothing worth talking about them, but here is.

First off, when words are suffixed to other words in Japanese, the pronunciation of the first syllable may suffer change.

me 目
Eye.
tama 玉
Ball.
medama 目玉
Eyeball.

Above, tama たま became dama だま. A diacritic, dakuten 濁点, was added to the first syllable of the suffix. This type of change is rendaku 連濁.

Another type is called sokuonbin 促音便, in which adds a small tsu っ between the words.

nichi 日
Day.
ki 記
Account. (in the sense of recording events.)
nikki 日記
Diary.

Above, nichi にち and ki き fused into nikki にっき.

Not all combinations are actually compounds. In Japanese, the kanji have meanings, such that multiple words sharing the same kanji often have similar meanings.

nyuugaku 入学
Enter school.
Enrolling a school.
nyuuin 入院
Enter clinic.
Being hospitalized.

However, that doesn't mean the kanji itself is a word. You can't say just nyuu 入 to say "enter," so it isn't a word, but you can say hairu 入る to say "to enter," so that is a word.

What is nyuu, then, if not a word? It's a morpheme.

Most nouns in Japanese are composed out of such morphemes, which are associated and spelled with kanji. This means that you can guess the meaning of a word from its kanji sometimes, since it works just like an adjective qualifying a noun.

chiisai onna
小さい女
Small woman.
shoujo
少女
Girl.
utsukushii shoujo
美しい少女
Beautiful girl.
bishoujo 美少女
(same meaning.)

Well, it doesn't always work like that.

minami 南
South.
kita 北
North.
nanboku 南北
~~Southy north.~~ (no.)
South-and-north. (yes.)

But it normally works like that.

Nouns as Adjectives

In Japanese, nouns can function as adjectives so long as they're marked by the genitive-case marking no の particle.

neko no mimi
猫の耳
Cat ears.
Ears of cats.
The cat's ears.

The way this works is extremely vague. Please see no の adjectives for details.

Pronouns as Nouns

In Japanese, sometimes pronouns are used just like nouns, in the sense that they're qualified by an adjective.

{binbou na} watashi
貧乏な私
The me [that] {is poor}.
The poor me.

Phrases like above, "the poor me," aren't all that awkward in English. However, in Japanese, specially spoken by anime villains, you'll see phrases like:

kono ore da この俺だ
This me.

Which sound rather weird.

And then there's stuff like this:

{shabetta} kono neko
喋ったこの猫
This cat [that] {spoke}.

Which is perfectly grammatical but can sound weird the first time you see it.

Meaningless Nouns

In Japanese, some words work just like nouns but, unlike normal nouns, don't really refer to anything tangible by themselves. These words depend on being qualified by an adjective to gain concrete meaning.

There are two classes of such words.

The first class are light nouns like koto こと. The word koto こと refers to something.

That's it.

You can't tell what koto こと refers to until it's qualified by an adjective, although exceptions exist.

{yareru} koto wo yatta
やれることをやった
Did things [that] {could do}.
[I] did something [that] {[I] could do}.
[I] did what {[I] could do}.
[I] did everything {[I] could do}.

The second class are nominalizers, like no の. Their only function is turning words into nouns and literally mean nothing at all. They're purely syntactical.

{benkyou suru} no ga muzukashii
勉強するのが難しい
{Studying} is difficult.
- Here, no の was used in order to turn benkyou suru into a noun so the ga が particle could mark it.

Verbs as Nouns

In Japanese, there are three ways in which verbs can become nouns.

yomu no ga tanoshii
読むのが楽しい
Reading is fun.
kanji no yomi wo shiraberu
漢字の読みを調べる
To look up the reading of a kanji.
yomu ga ii
読むがいい
Reading is good.
Read it.

The first way is by nominalizing the entire clause, which the verb is part of. In this case, the noun refers to an action that is actually done.

The second way is by using the noun form of the verb, also called ren'youkei 連用形, masu stem, and other names. This refers to the acting and is normally used to describe how you do something about something else.

The third way is a bit more confusing, because it looks like the verb is being marked as the subject. Grammatically, only nouns can be marked as the subject, so a verb becoming subject like that doesn't make sense.

This stems from classical Japanese, in which the attributive form, rentaikei 連体形, of verbs could be treated as nouns and marked by particles.

The confusion comes from the fact that yomu 読む is also the predicative form, shuushikei 終止形, of that verb. So both forms look the same way in modern Japanese, but the attributive form can be used as a noun.