Monday, December 31, 2018

Relative Clauses

Relative clauses, or adjective clauses, are, literally, clauses that work as adjectives to modify nouns. Now, that might sound a bit complicated and grammatical if the only clause you know is Santa, but it basically means that you can use verbs to describe things. For example:

neko ga shaberu 猫が喋る
The cat talks.

shaberu 喋る
To talk. (a verb.)

shaberu neko 喋る猫
The cat [that] talks

...that talks:
A relative clause.

In the example above, we aren't talking about any one cat. We're talking about the cat that talks, the talking cat, specifically.

In Japanese, relative clauses are called rentai-shuushoku-setsu 連体修飾節, "prenominal modifying clause," since they're clauses that come before nouns to modify them.

English Relative Pronouns

Wildcard Nouns

Grammar

In Na-Adjective Clauses

Passive Form and Transitiveness

With Verb in Causative Form

Cheat Sheet

English Relative Pronouns

In English, relative clauses and relative pronouns go hand in hand. Not every time, but a lot of time a relative clause is introduced by a relative pronoun. The most common relative pronouns are: that, who, whose, whom, and which.

The cat that speaks.
The cat who speaks.
The cat which speaks.
The cat whose abilities include speaking.
The cat whom you're speaking to.

That, Which, Who

A cool thing about the relative pronouns "that," "which," and "who," is that they're kind of nuanced: depending on the relative pronoun used, and how they're used, it affects what the phrase means.

The cat that speaks.

Restrictive clause.
We have, like, a hundred cats, and we're restricting the scope to that one cat that speaks.

The cat who speaks.

We're treating the cat as a person.
We wouldn't say "the chair who's missing a foot," because chairs are inanimate things.

The cat, who speaks, stayed quiet.

This a non-essential relative clause.
It adds information about the cat, but we can remove it.
The cat stayed quiet.

The cat which speaks.

Often the same thing as the cat that speaks.
Sometimes implies you're choosing between two or more cats. Which one? The one which speaks.

And that's cool and all, but: Japanese doesn't have relative pronouns.

Yep.

Japanese doesn't have relative pronouns.

All the nuance of English relative pronouns is lost in Japanese. Because Japanese puts literally nothing between the noun and its relative clause:

shaberu (literally nothing) neko 喋る猫
shaberu neko 喋る猫
The cat [that] speaks.
The cat [who] speaks.
The cat [which] speaks.

Therefore, we can't say for sure the word is "that," "who," or "which" in Japanese, because those literally aren't words in Japanese. We're just making up words for the translation that weren't said in Japanese so the translation makes sense in the English grammar syntax.

Further yet, we are [assuming] the Japanese phrase means one thing which it hasn't literally or explicitly said.

Of course, a good translator would spend a few seconds figuring out which is the right relative pronoun. But I assume your career isn't translating Japanese, from manga, anime, songs, tweets, etc. to English. So my advice is to not care and focus on understanding the phrases in Japanese.

Whose

We use the relative pronoun "whose" to describe something by something it has. Japanese doesn't have the relative pronoun "whose" either. You literally got to figure out whether we're talking about something that's part of something else or not. Which, to be honest, isn't that hard.

shippo ga shiroi desu しっぽが白いです
Tail is white.
shippo ga shiroi しっぽが白い
Tail [is] white.
shippo ga shiroi neko しっぽが白い猫
Cat [whose] tail [is] white.
shippo no shiroi neko しっぽの白い猫
(...same as above.)

Not every time you have a phrase in the pattern above the translation will get a "[whose]." For example:

shippo ga nai しっぽがない
Tail [is] non-existent.
[There is] no tail.
shippo ga nai neko しっぽがない猫
shippo no nai neko しっぽのない猫
Cat [without] tail.

Furthermore, we can have a phrase without a relative clause in Japanese that, in English, becomes a relative clause introduced by [whose]. This specially happens when you have the genitive case, with no-adjectives. For example:

shiroi shippo 白いしっぽ
White tail.
shiroi shippo no neko 白いしっぽの猫
White-tail cat. (literally.)
Cat [whose] tail [is] white. (naturally.)

Whom

We use the relative pronoun "whom" when describing something by an action done upon the thing. Japanese doesn't have "whom" either. What gets translated as "whom" is normally a relative clause with a transitive verb missing an object (which would be marked by wo を or ni に.)

For example:

ninja ga hito wo koroshita 忍者が人を殺した
The ninja killed a person.
ninja ga koroshita 忍者が殺した
The ninja killed (someone or something.)
ninja ga koroshita hito 忍者が殺した人
ninja no koroshita hito 忍者の殺した人
The person [whom] the ninja killed.

ninja ga neko ni ninjutsu wo oshieta 忍者が猫に忍術を教えた
The ninja taught the cat ninja-arts.
ninja ga ninjutsu wo oshieta 忍者が忍術を教えた
The ninja taught ninja-arts. (to whom?)
ninja ga ninjutsu wo oshieta neko 忍者が忍術を教えた猫
The cat [whom] the ninja taught ninja-arts.

Again, this pattern won't necessarily translate to "whom" either, because, to begin with, using "whom" in English is rather unusual and has some pretty restrict requirements.

ninja ga neko ni oshieta 忍者が猫に教えた
The ninja taught the cat. (what?)
ninja ga neko ni oshieta ninjutsu 忍者が猫に教えた忍術
The ninja-arts [which] the ninja taught the cat.

You don't say "the ninja-arts [whom]" 'cause ninja-arts ain't people.

sakka ga shousetsu wo kaita 作家が小説を書いた
The author wrote a novel.
sakka ga kaita shousetsu 作家が書いた小説
sakka no kaita shousetsu 作家の書いた小説
The novel [which] the author wrote.

Relative Adverbs

Relative adverbs are just like relative pronouns, except they aren't pronouns, they're adverbs. Such relative adverbs are: where, when, why, how, etc.

The day when it rained money.
The place where it rained money.
The reason why it rained money.
The way how it rained money.

As you've probably guessed already, Japanese doesn't have relative adverbs. You just connect stuff directly. Again.

kane ga futte-kita 金が降ってきた
Money came [down] raining.
Money rained.
[It] rained money.
kane ga futte-kita hi 金が降ってきた日
Day [when] money rained.
kane ga futte-kita basho 金が降ってきた場所
Place [where] money rained.
kane ga futte-kita riyuu 金が降ってきた理由
Reason [why] money rained.
kane ga futte-ktia houhou 金が降ってきた方法
Method [how] money rained.

So Japanese doesn't have relative pronouns or relative adverbs, however, it does have relative clauses, a.k.a. adjective clauses, which we use to modify nouns.

Wildcard Nouns

The relative pronouns and relative adverbs, which Japanese doesn't have, exist in English for a reason: they mean stuff. Without them, Japanese must put all that meaning somewhere else, and that place would be: in nouns.

If you've been learning Japanese for some time you've probably already met a noun or two which holds certain mysterious, mystical properties. The way they're translated makes you question whether they're actually nouns or all the Japanese dictionaries in the world are trolling you.

For example:

terebi wo miru toki wa heya wo akaruku shite hanarete mite kudasai
テレビを見るときは部屋を明るくして離れて見てください
When watching TV, keep the room well-lit and don't watch from too close.

Why is toki とき, a noun that means literally "time," translated as "when" up there? Is "when" even a noun. *checks dictionary* No! It's not! It's an "adverb" and "conjunction!" ^{["when" - dictionary.cambridge.org, 2018-12-19]}

The reason for this is that, if we translate literally, we get this monstrosity:

Time [in which you] watch TV: make the room lit and distantiate and watch, please.

Some other examples of these weird nouns that are always used with relative clauses or other kinds of adjectives are:

tada no shikabane no you da
ただのしかばねのようだ
The appearance of a mere corpse.
It seems to be just a corpse.
shinda you da
死んだようだ
The appearance [that it] died.
It seems [it] died.

kimi no tame nara nandemo shimasu!
君のためならなんでもします！
If [it's for] your sake [I'll do] anything!
I'll do anything for you!
katsu tame nara nandemo suru
勝つためならなんでもする
If [it's for] the sake [which is] to win [I'll do] anything.
To win [I'll] do anything.

kigaeteru toko mirareta
着替えてるとこ見られた
kigaeteru tokoro mirareta
着替えてるところ見られた
The event [in which I was] changing clothes was seen.
[I] was seen [while] changing clothes.

mita koto nai
見たことない
The case [in which] [I] saw [it] [is] nonexistent.
[I] have never seen it.

Nomenclature

The nomenclature of such nouns is kind of complicated.

A "dependent noun" is a noun that doesn't make sense alone, and must always come after an adjective, including relative clauses, like the above. For example, can you use toko as the first thing in a phrase? Err... no...? Probably not? I don't know. I guess not. Could be wrong though.

And therein lies a problem: you can't say a noun is a "dependent noun" unless you're 100% certain it's always dependent. So some people call them "auxiliary nouns" instead.

Linguistically, they've also been called "light nouns," due to their lack of semantic meaning compared to their syntactical properties, and "nominalizers," since they're mostly used to turn verb phrases into noun phrases instead.

Nominalizers

In The Grammaticalization of Nominalizers in Japanese and Korean, Kaoro Horie notes the Japanese language prefers statements as noun phrases rather than verb phrases, unlike English.

This preference means they tend to use nominalizers to turn their disliked verb phrases into the superior noun phrases they like so much. Even when it's apparently totally unnecessary.

shinda! 知らない！
[It] died!
(a verb phrase)
shinda mon! 死んだもん！
shinda mono! 死んだもの！
[It] died!
(a noun phrase, since it ends with a noun.)

mon もん
A nominalizer, adds literally zero meaning.
Often used by children, so I suppose it adds nuance.
Comes from mono もの, also a nominalizer.
da mon だもん
desu mono ですもの
Also contain this nominalizer.

Furthermore, this preference is probably the root of why there are so many nominalizers in Japanese.

That is, in English we like to use relative pronouns and relative adverbs to introduce relative clauses. Pretty much all relative clauses could be introduced with "in which," but that doesn't sound meaningful enough, so we have a plethora of different pronouns and adverbs, each with its own nuance, to meaningfully introduce the relative clauses: that, which, whose, where, when, how, etc.

In Japanese, no の is the most basic, most meaningless nominalizer, and the less used too. Because people prefer to use more meaningful nominalizers that add nuance to the phrase: koto, toko, tokoro, mono, toki, etc.

tatakatteiru no wo mita
戦っているのを見た
[I] saw the fighting.
tatakatteiru toko wo mita
戦っているとこを見た
[I] saw the event [in which there was] fighting.
[I] spotted the fighting.
[I] spotted [you] fighting.
[I] saw [you while you were] fighting!

Grammar

Basic Usage

The basic way to use relative clauses in Japanese is to simply add the noun after a stand-alone clause.

neteiru 寝ている
[To be] sleeping.
neteiru hito 寝ている人
Person [that is] sleeping.
Sleeping person. Sleeping people.

taiyou no te wo motsu 太陽の手を持つ
To have solar hands.

motsu 持つ
To hold (in hands.)
To have.

taiyou no te wo motsu shounen 太陽の手を持つ少年
The boy [who] has solar hands.
The boy [that] has solar hands.
The boy [with] solar hands.

Note above how "have solar hands" became "has solar hands" in the relative clause in English, despite the relative clause staying the same in Japanese. This is another trivial detail that you shouldn't worry about.

With Verb in Non-Past Form

Japanese only has two times: past and non-past. If the verb of the relative clause is in non-past, it can either mean the action "happens," i.e. "is happening," or "will happen." This is used when we want to describe a noun by something it does. For example:

nagareru 流れる
To flow. To stream. To run (liquid.)
nagareru mizu 流れる水
Water [that] flows. Water [that] streams. Water [that] runs.

If it's a water that runs, then it runs, even now.
Since it's constantly running, we can also say it's:
Running water.
But that's normally what we call about water in houses, so...
Streaming water. Flowing water.

kieru 消える
To disappear.
kieru tatwuu 消えるタトゥー
A tattoo [that] disappears.

Obviously, the tattoo doesn't appear and disappear constantly.
It disappears once, then it's gone.
So kieru, in this case, is something that "will happen."
"A tattoo [that] will disappear (after a while.)"

With Verb in Past Form

If the verb is in past form, it's a lot more simple: we're describing the noun by something it has done, in the past:

nagareta mizu 流れた水
Water [that] has flowed.

Implying it no longer flows.

kieta tatwuu 消えたタトゥー
Tattoo [that] disappeared.

Implying it was there once, now it's gone.

You'll see that it's more common to use verbs in relative clauses in past form than in non-past form.

That's because non-past describes the nature of a thing. What that thing does, normally. That's fine to describe something new or of specific nature, like a "flying car," but usually you want to describe—or rather, specify—something by an event which occurred it in the past, e.g. "the car I bought."

With Verb in Negative Form

If the verb is in the negative form, as one would expect, it means something doesn't happen, isn't happening, or will not happen in the non-past, or hasn't happened in the past.

As always, the negative form is created by using the nai ない auxiliary adjective that's inflected like an i-adjective to past: nakatta なかった.

kienai tatwuu 消えないタトゥー
Tattoo [that] does not disappear.
Tattoo [that] will not disappear.

Yep. It's permanent.

kienakatta tatwuu 消えなかったタトゥー
Tattoo [that] did not disappear.

Uh... wait, does this mean it should have disappeared, but did not?
Yeah, that sounds like trouble.
That sounds bad.

With Verb in Tai Form

When a verb is in the tai form, with the -tai ～たい auxiliary, also called desiderative mood, it means "[you] want to do (the verb.)" In a relative clause, it mean "[you] want to do (the verb) with (the noun.)"

For example:

yaru やる
To do.
yaritai やりたい
Want to do.
yaritai koto やりたいこと
Something [that I] want to do.
yaritai geemu やりたいゲーム
A game [that I] want to do.
A game [that I] want to play.

tabetai 食べたい
Want to eat.
tabetai mono 食べたいもの
Something [that I] want to eat.

mitai anime 見たいアニメ
An anime [that I] want to see.

The tai auxiliary can be inflected like an i-adjective, to past, negative, past negative, etc. These also work in relative clauses:

mitakatta anime 見たかったアニメ
Anime [that I] wanted to see.
mitakunai anime 見たくないアニメ
Anime [that I] do not want to see.
mitakunakatta anime 見たくなかったアニメ
Anime [that I] did not want to see.

With Verb in Potential Form

When the verb of the relative clause is in potential form, it means something that can happen. Or, in the potential past, could have happened.

katsu 勝つ
To win.
kateru 勝てる
To be able to win.
kateru aite 勝てる相手
An adversary [which I] can win [against.]
kateta aite na-no-ni maketa 勝てた相手なのに負けた
[It was] an adversary [which I] could win [against,] despite this, [I] lost.

In anime, a remarkable way this shows up is when a character says he will use anything and anybody he can to achieve a goal. For example:

tsukaeru koma wo subete tsukau 使えるコマをすべて使う
Use all pieces [that] can be used.
uteru te wo subete utsu 打てる手をすべて打つ
Deal all hands [that] can be dealt.

Of course, this works in the negative too:

yomu 読む
To read.
yomeru kanji 読める漢字
Kanji [that I] can read.
yomenai kanji 読めない漢字
Kanji [that I] can't read.
yomenakatta kanji 読めなかった漢字
Kanji [that I] couldn't read.

taosu 倒す
To defeat.
taoseru 倒せる
To be able to defeat.
taoseru teki 倒せる敵
Enemy [which I] can defeat.
Vincible enemy.
taosenai teki 倒せない敵
Enemy [which I] can't defeat.
Invincible enemy.

Ga が Becoming No の in Relative Clause

In relative clauses, when you have a subject, sometimes the subject-marking particle ga が can become no の instead. For example:

kane ga aru 金がある
Money exists.
[There is] money.
[To have] money.

kane is the subject marked by ga.

kane ga aru hito 金がある人
kane no aru hito 金のある人
Person [who has] money.

Such change makes the relative phrase look like a no-adjective, but it's not a no-adjective: it's a relative clause.

In Na-Adjective Clauses

Note that, technically, na-adjectives are actually relative clauses ending with a copulative verb. Since they're relative clauses, they share the concept of switching ga for no. For example, we can have a phrase like this:

Manga: Karakai Jouzu no Takagi-san からかい上手の高木さん

Context: Nishikata uses frog.
douda----!!
どうだーー！！
[How's this!!]
kaeru no nigate na joshi wa ooi to kiku
カエルの苦手な女子は多いと聞く
[You] hear that there are many girls [to whom] frogs are hard-to-handle!
[Everyone says that] lots of girls hate frogs!

What's happening above is that we have this clause:

kaeru ga nigate da カエルが苦手だ
Frogs are hard-to-handle.

nigate 苦手
Hard-to-handle. (literally.)
Generally it means to someone something is "hard to handle," as a single-word adjective.
It could be they don't like it. Because it's disgusting, or annoying, etc.
They hate it.
[I hate frogs.]

First, the predicative copula da だ is replaced by the attributive copula na な.

kaeru ga nigate na カエルが苦手な

This turns the predicative clause into an attributive clause. An "attributive clause" is just another name for an "adjective clause" or "relative clause."

Since it's a relative clause now, you can put it before a noun, just like any other relative clause.

kaeru ga nigate na joshi カエルが苦手な女子

And since it's a relative clause, we can replace the subject-marking ga が by no の.

kaeru no nigate na joshi カエルの苦手な女子
Girls [to whom] frogs are hard-to-handle.
Girls [who] hate frogs.

To reiterate: the verb of the relative clause above is na な. That doesn't look like a verb at all, but technically it's a verb. It's just like how da だ is a copula, a copulative verb. Since na な is also a copula, it's also a copulative verb.

The trick here is that normally you'd use the same verb in a relative clause that you'd use elsewhere. But with copulas, you use da だ in the predicative clause, and na な in the relative clause. Once you get that, it all makes sense.

Passive Form and Transitiveness

It's important to pay attention to the transitiveness of the verb of the relative clause. That's because, normally, you'll want an intransitive verb, not a transitive one.

With a transitive verb, you have an agent, who does the action, and a patient, who receives the action. In other words: you have two arguments.

If you put a transitive verb before a noun, that noun becomes one of those two arguments. But that means there's also another argument somewhere, explicit or implicit, and that might cause confusion.

殺した人 vs. 殺された人

To understand this better, let's see an example:

korosu 殺す
To kill.

Transitive: subject kills object.

kare ga hito wo koroshita 彼が人を殺した
He killed a person.

Who killed?
kare
So kare = agent.
Killed whom?
hito
So hito = patient.

kare ga koroshita hito 彼が殺した人
kare no koroshita hito 彼の殺した人
Person [that] he killed.

Notice above how hito is the patient of the verb korosu, even when being modified by a relative clause. If hito is the patient, who is the agent doing the killing? That's clearly kare, as it's also the subject, marked by the particles ga or no, and the subject is normally the agent.

But here's what happens if we remove kare from the phrase:

koroshita hito 殺した人
Person [that I] killed.

Whoa whoa whoa. Wait a second there. I didn't kill nobody. Why does that phrase implies I did something like that?

Well, that's because: the relative clause is missing the subject. When we don't have a subject in Japanese we normally assume the subject is the speaker, which is I. For example, if we remove hito from the phrase above, we get:

koroshita 殺した
[I] killed.

The only way to avoid ~~jail time~~ confusion is to use a verb that's intransitive. In this case, it would be the passive conjugation of korosu.

korosareru 殺される
To be killed.
Will be killed.

Who will be killed?
[implicit]
Since we have no explicit subject, we assume it's the speaker, "I."
"[I] will be killed."
korosareru!!! tasukete!!!
殺される！！！助けて！！！
[I'm] gonna be killed!!! Help [me]!!!

hito ga korosareta 人が殺された
A person was killed.
korosareta hito 殺された人
Person [that] was killed.

As you can see above, when we have a verb conjugated to its passive form, the clause becomes in passive voice, so the subject (marked by ga が) becomes the patient instead of the agent, the one whom someone killed rather than the one who kills.

殺された人が殺した人を殺す

Normally, one would assume the implicit subject is the speaker, however, there are cases that doesn't happen. For example:

korosareta hito ga koroshita hito wo korosu
殺された人が殺した人を殺す
The person [who] was killed kills the person [who] killed.

In the phrase above, koroshita hito refers to the hito who koroshita the korosareta hito, i.e. someone was killed, someone killed, and koroshita hito refers to the one who killed, not the one being killed.

koroshita hito 殺した人
Person [that] [I, or someone,] killed. (normally.)
Person [that] killed [someone]. (this case.)

彼に殺された人

In Japanese, the agent in a passive voice sentence is marked by the particle ni に. This works both in predicative and attributive (relative clauses).

hito ga kare ni korosareta 人が彼に殺された
Person was killed by him.
People were killed by him.
kare ni korosareta hito 彼に殺された人
Person [that] was killed by him.
People [that] were killed by him.

家族を殺された人

In relative clauses, sometimes the wo を particle is used with a verb in the passive form so to avoid implying the noun the relative clause modifies is the agent of that clause.

This can be a bit confusing because in the predicative form it would look like we have two patients:

X wo koroshita ◯を殺した
Killed X.

X is marked as the direct object.
So X is the patient.

X ga korosareta ◯が殺された
X was killed.

X is marked as the subject.
The verb is in passive form.
The voice is passive.
So X is the patient.

X ga Y wo korosareta ◯が△を殺された

X is subject in the passive voice, so it's the patient.
Y is marked by wo, so it's the direct object, so it's the patient.
We have two patients???

What happens is that Japanese grammar isn't as clear-cut as you'd wish it were.

Traditionally, a clause has a subject, and everything else is the predicate. Since half of the time this "predicate" contains a verb, it's easy to assume the subject must be an argument for that verb in some way. That is, the subject must be either doing the action, or having the action done upon it.

Clearly, that's not the case here. Here, the ga が subject-marker feels closer to the topic-marker wa は, and the subject feels closer to a topic. What's said about a "topic," by the way, is called the "comment." So:

kare ga kazoku wo koroshita 彼が家族を殺した
He killed the family.
He killed [his] family.

In active voice, the subject is the agent.

kare ga kazoku wo korosareta 彼が家族を殺された
About him: family was killed.
[His] family was killed.

In passive voice, with a direct object marked by wo を, the subject isn't the agent.
It simply becomes so that the predicate is something said about the subject.

Since it works like that in the predicative, it follows that it'd work like that in the attributive, with a relative clause:

kazoku wo koroshita hito 家族を殺した人
A person [that] killed [their] family.
kazoku wo korosareta hito 家族を殺された人
A person [who had a] family [that someone] killed.
A person [whose] family was killed.

To make matters more complicated, you can even include the agent explicitly with the ni に particle.

shujinkou ga ninja ni kazoku wo korosareta
主人公が忍者に家族を殺された
About the main-character: [his] family was killed by ninjas.
ninja ni kazoku wo korosareta shujinkou
忍者に家族を殺された主人公
Main-character [whose] family was killed by ninjas.

With Verb in Causative Form

When the verb of the relative clause is in the causative, it should mean someone has forced or let someone else do something.

The causative is always transitive. That's because if you (subject) die, that's intransitive, there's no object for the verb "to die." But if you (subject) force/make/let someone (object) die, then we have both subject and object. Any intransitive verb becomes transitive in the causative.

As we've already seen, when we have a transitive verb in the relative clause, the noun the relative clauses modified is assumed to be the object of the verb. So:

shinu 死ぬ
To die.
shinaseru 死なせる
To let (someone) die.
To force (someone) to die.
neko wo shinaseta 猫を死なせた
[I] let the cat die.

i.e. [I] didn't do enough to protect the cat!
The car ran all over him!
He's in another world now.
With a harem of 72 cat-girls, probably.

shinaseta neko 死なせた猫
Cat [whom I] let die.

Practically Causative Verbs

A number of verbs which you wouldn't say are conjugated to their causative forms are, in practice, the causative version of other verbs.

In these cases, again, pay attention to the transitiveness of the verb that's used. Since the transitive may imply the speaker has taken part in the action.

nigeru 逃げる
To run away. To escape.
nigasu 逃がす
To let run away. To Escape.
nigeta teki 逃げた敵
The enemy [who] escaped.
nigashita teki 逃した敵
The enemy [whom I] allowed escape.

You allowed enemies to escape with your incompetence!!! Commit sudoku!!!

miru 見る
To see.
miseru 見せる
To show. To force/make/let see.
mita mono 見たもの
Something [that I] saw.
miseta mono 見せたもの
Something [that I] showed [to someone.]
Something [that someone] showed [to me].

The choice between the above can change the meaning of a phrase from "what do you think about what you saw" to "what do you think about what I showed you."

Causative Ambiguities

When a transitive verb is turned into causative, there's an added argument to the equation: the object from the non-causative verb. That is, when you see, you see something, so there's an object. If you show someone, you're showing someone something else.

In Japanese, it's grammatically ambiguous which argument exactly noun the relative clause modifies refers to. You have to guess from context. Added to that, sometimes the noun can be the subject too. So there's a lot of guessing going on.

miseta hito 見せた人

The person [who] showed [something to me.]
The person [to whom I] showed [something.]
The person [that I] showed [to someone.]
The person [that someone] showed [to me.]

Furthermore, the noun doesn't even need to actually be an argument of the verb. The noun could refer to the time, place, reason, method, etc. of the action.

miseta shunkan 見せた瞬間
The moment [when someone] showed [something to someone else.]

But none of this is as hard as it seems. After all, it's more likely a thing is being shown than a person is being shown. So miseta hito probably means the hito showed something, or was shown something, rather than the hito itself was shown to someone else.

Conversely, if the noun is a thing, it's more likely it's being shown than it's showing or being shown to.

miseta mono 見せたもの

~~The thing [which] showed [something to me.]~~
Probably not.
~~The thing [to which I] showed [something.]~~
Nope.
The thing [which I] showed [to someone else.]
Probably yes.
The thing [which someone] showed [to me.]
Yep.

When the phrase is longer than two words, a lot of these ambiguities vanish.

sainou wo miseta hito 才能を見せた人
Person [who] showed talent.
kare ni miseta mono 彼に見せたもの
The thing [I] showed to him.
kare ga miseta mono 彼が見せたもの
The thing he showed [to me].

With Personal Pronouns

Relative clauses can come before personal pronouns in Japanese, just like any other adjective can. This can be a bit surprising from an English perspective, but it kinda works just fine. See:

ganbaru 頑張る
To try one's best. To put effort in something. To persevere.
ganbatteiru 頑張っている
To be trying one's best. (te-iru form.)
kanojo ga ganbatteiru 彼女が頑張っている
She's trying her best.
ganbatteiru kanojo wo mita 頑張っている彼女を見た
[I] saw her [while she was] trying her best.

iu 言う
To say. To tell.
iwareru 言われる
To be told. (passive.)
iwaretai 言われたい
To want to be told. (passive tai form.)
iwaretakunai 言われたくない
To not want to be told. (negative passive tai form.)
nigeta omae ni iwaretakunai 逃げたお前に言われたくない
[I] don't want to be told [this] by you [who] escaped.

yomigaeru 蘇る
To resurrect. (intransitive.)
yomigaeraseru 蘇らせる
To make [someone] resurrect. (causative.)
To revive [someone].
shinda ore wo yomigaeraseta 死んだ俺を蘇らせた
Revived me [who had] died

Wa は in Relative Clauses

You don't use the wa は particle in relative clauses. However, there's a couple of things worth noting.

dewanai ではない

The wa は can show up as part of dewanai ではない that comes after a na-adjective or no-adjective. Because this dewanai has a contrastive nuance, the non-nuanced denai is sometimes used instead.

baka denai hito 馬鹿でない人
baka dewanai hito 馬鹿ではない人
A person [that] is not stupid.

In Adverbial Clauses

The wa は can also show up in an adverbial clause. But adverbial clauses aren't relative clauses; they're a different kind of subordinate clause.

erufu wa mimi wa nagai エルフは耳は長い
As for elves, their ears [are] long.

The phrase above can have either of the following implications:

The elves, unlike other races, have long ears.
The ears of elves, unlike other body parts, are long.

Safe to assume above we're talking about the first case, not the second.

After the Relative Clause

Although the wa は doesn't show up in the relative clauses themselves, they do often show up right after the noun the relative clause modifies. For example:

ganbatteiru hito wa kakkoii!
頑張っている人はかっこいい！
People [who] try [their] best [are] cool!

With Beki べき

Sometimes a relative clause ends with the auxiliary beki べき rather than a verb. This beki adds the meaning of something that should happen, should be done, should be, etc.

kimi ga iru beki basho 君がいるべき場所
The place [where] you should be.
yaru beki koto やるべきこと
nasu beki koto なすべきこと
suru beki koto するべきこと
Thing [that someone] should do.
What must be done. What I must do. What I have to do.

Nested Relative Clauses

Like in English, Japanese relative clauses can contain other relative clauses. That is, you can qualify a noun with a relative clause that contains a noun qualified by another relative clause. For example:

{mitai} anime 見たいアニメ
Anime {that I want to watch}.
{{mitai} anime wo miru} jikan 見たいアニメを見る時間
Time {in which I watch anime {that I want to watch.}}
{{mitai} anime wo miru} jikan ga nai!! 見たいアニメを見る時間がない！！
I don't have time {to watch the anime {I want to watch!!}}

Relative clauses can also be nested with other kinds of adjectives.

hito no tamashii 人の魂
A person's soul.
The soul of a person.
shinda hito no tamashii 死んだ人の魂
The soul of a person [that] died.

shiroi hana 白い花
White flower.
hajimete mita shiroi hana deshita 初めて見た白い花でした
[It] was the white flower [that I] first saw.

An important thing about nested relative clauses, or rather, clauses in general, is that things such as subject, direct object, etc. are syntactically limited to one per clause. This means you can have two object-marking wo を particles in the same clause, but in different clauses it's alright.

jibun wo shinjiru kokoro wo motte
自分を信じる心を持って
Have a heart [that] believes in yourself.
(i.e. have faith in yourself.)

"Oneself" is object for "to trust."
"The heart that trusts oneself" is object for "to have."

Grammatically, you can nest as many as you want, but since it turns the phrase into a mess, both in Japanese and in English, people generally don't keep nesting relative clauses like Matryoshka dolls.

nezumi wo kutta
neko wo kutta
inu wo kutta
ネズミを食った
猫を食った
犬を食った
ate the dog [that]
ate the cat [that]
ate the rat.

Cheat Sheet

For reference, a cheat sheet.

Source: japanesewithanime.com (CC BY-SA 4.0)

Examples

Some more examples of relative clauses in Japanese.

inaka de yaru koto nai
田舎でやることない
In the countryside, there's no thing [that you] do.
There's nothing to do in the countryside.

tsumaranai つまらない！
[It's] boring!

jibun ga yatta koto wo oboetenai
自分がやったことを覚えてない
Doesn't remember the thing [that] oneself did.
I don't remember what I have done.

kioku soushitsu! 記憶喪失！
Amnesia!

yaritai koto ippai aru
やりたいこといっぱいある
There is a lot of things [that I] want to do.
I want to do lots of things.

tanoshii~~ たのしい～～
Fun~~

yaru beki koto やるべきこと
Thing [that I] should do.
yareru koto やれること
Thing [that I] can do.

watashi-tachi ga dekiru koto
私達ができること
The things [that] we can do.
Let's do everything we can to help the main-character!

kikitai koto 聴きたいこと
Something [I] want to ask. (hear.)
shiritai koto 知りたいこと
Something [I] want to know.
kiku koto nado nanimo nai
shiritai koto wa shitteiru.
聞くことなどなにもない
知りたいことは知っている。
There's nothing [I] want to ask.
What [I] want to know [I already] know.
— Balalaika, from manga Black Lagoon.

aisuru hito 愛する人
Person [whom I] love.
Person [that] loves.
jiakn wo ayatsuru nouryoku 時間を操る能力
The ability [that is] manipulating time.
The ability to manipulate time.

sukuwareta inochi 救われた命
Life [that was] saved.
ushinawareta inochi 失われた命
Life [that was] lost.

nigeru tsumori 逃げるつもり
The intent [that is] escaping.
The intent to escape. Intending to escape.
He's trying to run away!
nani wo suru tsumori? 何をするつもり？
The intent [that is] doing what?
What do you intend to do?
What do you plan to do?
What are you gonna do?

ikiru tame ni tatakau 生きるために戦う
To fight for the sake [that is] living.
To fight in order to live.

kare wa shinda hazu da! 彼は死んだはずだ！
As for him, [it's] the expectation [that he] died!
He's supposed to have died!
He's supposed to be dead!
kare wa shinda wake da 彼は死んだわけだ
As for him, [it's] the conclusion [that he] died.
Thus he died. Because of all that he died.
kare ga shinda riyuu 彼が死んだ理由
The reason [why] he died.
Why he died.

ore no doriru wa ten wo tsuku doriru da!!!
俺のドリルは天を着くドリルだ！！！
My drill is a drill [that] pierces the heavens!!!

Rama ni Natta Ou-sama
ラマになった王様
The King [that] Became a Llama.

kimi ga nozonda sekai 君が望んだ世界
The world [that] you wished for.
kimi ga eranda michi 君が選んだ道
The path [that] you chose.
te ni ireta chikara 手に入れた力
The power [that] entered [my] hand.
The power [that I] obtained.
kaita tegami 書いた手紙
Letter [which I] wrote.
mitsuketa mono 見つけた物
Thing [which I] found.

kamisama ga inai nichiyoubi 神様がいない日曜日
Kamisama no Inai Nichiyoubi 神様のいない日曜日
Sunday [in which] God Isn't.
Boku Dake ga Inai Machi 僕だけがいない街
The Town [where] Only I'm Not.
Mondaiji-tachi ga Isekai kara Kuru Sou Desu yo?
問題児たちが異世界から来るそうですよ?
[It's] the appearance [that] problem children are coming from another world.
It Appears Problem Children are Coming From Another World.
Zero Kara Hajimeru Isekai Seikatsu
ゼロから始める異世界生活
Another World Life [that someone] Starts From Zero.

nemuru toki 眠るとき
Time [when you] sleep.
When [you] sleep.
When sleeping.
nemuru mae 眠る前
Before [the time when you] sleep.
Before [you] sleep.
Before sleeping.
nemuru ato 眠る後
After [the time when you] sleep.
After [you] sleep.
After sleeping.
nemuru shunkan 眠る瞬間
The instant [in which you] sleep.
nemuru totan 眠る途端
The exact moment [when] you sleep.
nemuru koro 眠るころ
Around the time [when you] sleep.