Simple, Compound & Complex Sentences in Japanese ─ Why Sentence Structure Matters in Deaf Education

Introduction: knowing how a sentence is built makes Japanese easier to read

Depending on how they are put together, Japanese sentences fall into three types: simple (単文, tanbun), compound (重文, jubun) and complex (複文, fukubun). We rarely stop to think about it in daily life, but once you understand this "skeleton of the sentence," long and complicated sentences become much easier to make sense of. It is a foundation for both reading and writing.

This sentence structure is also a theme we very much want to value in the field of deaf education. In this article, I will first lay it out gently as ordinary grammar, and then in the second half consider "why it matters in deaf education."

The four parts that build a sentence: subject, predicate, modifier, connective

When we think about how a sentence is built, the most basic foundation is the relationship between the subject and the predicate (the subject-predicate relation, 主述関係).

• Subject (主語, shugo): the part that shows "what" or "who" (e.g. 犬が inu ga, "the dog"; 子どもが kodomo ga, "the child")
• Predicate (述語, jutsugo): the part that shows "does what / is how / is what" (e.g. 走る hashiru, "runs"; 笑う warau, "laughs"; 元気だ genki da, "is well"; 学生だ gakusei da, "is a student")

In 「犬が走る」 (inu ga hashiru, "the dog runs"), 「犬が」 is the subject and 「走る」 is the predicate. It is how many subject-predicate relations there are, and how they connect, that divides sentences into simple, compound and complex.

Besides the subject and predicate, a sentence has two other important parts.

• Modifier (修飾語, shushokugo): a word that describes another word in more detail. The bold parts in 「赤い花」 (akai hana, "a red flower") and 「ゆっくり歩く」 (yukkuri aruku, "walk slowly").
• Connective (接続語, setsuzokugo): a word that joins sentences or words together. 「そして」 (soshite, "and then"), 「しかし」 (shikashi, "however"), 「〜ので」 (-node, "because"), 「〜ば」 (-ba, "if"), and so on.

It is the way these "modifiers" and "connectives" are used that creates the difference between the compound and complex sentences we look at next.

Simple sentence (tanbun): just one subject-predicate pair

A simple sentence (単文, tanbun) has only one subject-predicate relation.

• 子どもが 笑う。 (Kodomo ga warau. — "The child laughs.")
• 妹は ケーキを 食べた。 (Imouto wa keeki o tabeta. — "My little sister ate the cake.")
• この花は とても きれいだ。 (Kono hana wa totemo kirei da. — "This flower is very pretty.")

Even if you add more modifiers (「とても」 totemo "very," 「赤い」 akai "red," and so on), as long as there is a single subject-predicate pair, it is still a simple sentence. It is the most basic form, and its meaning is easy to grasp.

Compound sentence (jubun): equal clauses set side by side (coordination)

A compound sentence (重文, jubun) has two or more subject-predicate relations, and they are set side by side as equals. Neither is part of the other; they stand shoulder to shoulder (a coordinate, or side-by-side, relation, 並立関係).

• 姉は ピアノを ひき、妹は 歌を うたう。 (Ane wa piano o hiki, imouto wa uta o utau. — "My older sister plays the piano, and my little sister sings a song.")
• 父は 新聞を 読み、母は 料理を する。 (Chichi wa shinbun o yomi, haha wa ryouri o suru. — "My father reads the newspaper, and my mother cooks.")
• 兄は 出かけたが、私は 家に 残った。 (Ani wa dekaketa ga, watashi wa ie ni nokotta. — "My older brother went out, but I stayed at home.")

Two independent sentences—「姉はピアノをひく」 ("my older sister plays the piano") plus 「妹は歌をうたう」 ("my little sister sings a song")—stand side by side as equals. A characteristic feature is that they are often joined by forms such as 「〜し、」 (-shi,), 「〜て、」 (-te,), 「〜が、」 (-ga,).

Complex sentence (fukubun): a clause nested inside another (subordination)

A complex sentence (複文, fukubun) has two or more subject-predicate relations, but one is nested inside the other. A separate clause (the subordinate clause, 従属節) is subordinate to the central sentence (the main clause, 主節)—serving as a modifier, condition, reason, time, and so on. In other words, it has a nested (subordinate) structure (主従関係).

• 私は ［姉が 焼いた］ パンを 食べた。 (Watashi wa [ane ga yaita] pan o tabeta. — "I ate the bread [that my older sister baked]." … the [ ] part describes 「パン」 "bread" — an adnominal modifier)
• 雨が ふれば、遠足は 中止だ。 (Ame ga fureba, ensoku wa chuushi da. — "If it rains, the field trip is cancelled." … 「雨がふれば」 "if it rains" expresses a condition)
• 弟が 帰ってきたとき、私は 本を 読んでいた。 (Otouto ga kaette kita toki, watashi wa hon o yonde ita. — "When my little brother came home, I was reading a book." … 「〜とき」 "when" expresses time)
• 道が こんでいたので、約束に 遅れた。 (Michi ga konde ita node, yakusoku ni okureta. — "Because the road was crowded, I was late for the appointment." … 「〜ので」 "because" expresses a reason)

For example, in 「姉が焼いたパンを食べた」 ("[I] ate the bread that my older sister baked"), 「私はパンを食べた」 ("I ate the bread") is the central sentence, and inside it the small clause 「姉が焼いた」 ("my older sister baked") is embedded to describe 「パン」 ("bread").

The three types of complex sentence

The clause embedded in a complex sentence (the subordinate clause) comes in three broad types.

How to tell compound and complex sentences apart

The table below sums up the difference.

The knack for telling them apart is simple.

• Two sentences set side by side as equals → compound
• One sentence has become a part of the other (a description, condition, reason, etc.) → complex

More elaborate sentences: compound and complex mixed together

In real writing, compound and complex often mix within a single sentence.

Example: 姉は ピアノを ひき、弟は ［母が 書いた］ 手紙を 読んだ。 (Ane wa piano o hiki, otouto wa [haha ga kaita] tegami o yonda. — "My older sister plays the piano, and my little brother read the letter [that my mother wrote].")

• 「姉はピアノをひく」 ("older sister plays the piano") plus 「弟は手紙を読んだ」 ("little brother read the letter") stand side by side as equals → the compound skeleton
• Inside that 「弟は手紙を読んだ」 sits 「母が書いた」 ("mother wrote"), an adnominal clause → a complex element

In this way, a long sentence is made by combining "parts that stand side by side (compound)" with "nested parts (complex)." Rather than panicking, the shortcut to decoding it is to find the subject-predicate relations one at a time.

In practice: reading a long sentence by breaking it down

Even a long sentence full of complex structure can be read once you break it down in order. Let's practise with the following sentence.

Example: 父が 駅で 買った 新聞を、私は 電車の 中で 読んだ。 (Chichi ga eki de katta shinbun o, watashi wa densha no naka de yonda. — "The newspaper that my father bought at the station, I read on the train.")

1. First, find the predicate → 「読んだ」 (yonda, "read")
2. Its subject? → 「私は」 (watashi wa, "I")
3. What did [I] read? → 「新聞を」 (shinbun o, "the newspaper")
4. What kind of newspaper? → 「父が 駅で 買った」 (chichi ga eki de katta, "that my father bought at the station" = an adnominal clause; here too there is a small subject-predicate: 「父が・買った」 "father / bought")

By splitting it this way into "the central sentence (I read the newspaper)" and "the embedded clause (my father bought at the station)," the meaning comes into clear view. The knack is to trace it in the order predicate → subject → object → modifier.

Why we want to value this in deaf education

Here is the heart of the matter. Sentence structure, and complex sentences (複文) in particular, carries great meaning for growing the Japanese-language abilities of deaf children and students.

The "nine-year-old wall" and abstract, complex Japanese

In deaf education, the phrase "the nine-year-old wall" (9歳の壁, kyuusai no kabe) has long been spoken of. It refers to a phenomenon in which, around the age of nine, children tend to feel a wall in their learning and language development—a point where they easily stumble as they move from concrete content to abstract content, and from simple sentences to complex ones.

While everyday simple sentences are picked up relatively early, stumbles tend to happen with abstract words and complex sentence structure (especially the complex sentence)—supporting children here, consciously, connects to the reading and learning abilities that come later. That said, this is thought of less as "a wall that will inevitably appear" and more as a challenge that can be eased by a rich language environment from an early age.

Why complex sentences are especially hard

There are several reasons why mastering complex sentences tends to be difficult.

• Nesting (adnominal modification): as in 「お母さんが 作った ケーキ」 (okaasan ga tsukutta keeki, "the cake that Mum made"), a clause is embedded inside a sentence. You have to read while holding the "who / what / did what" relationship in your head.
• Words that link logic: 「〜ので」 (-node, reason), 「〜のに」 (-noni, adversative), 「〜ば」 (-ba, condition), 「〜ても」 (-temo, concession) and the like—these connective words carry invisible, abstract relationships.
• Particles, and omitted subjects: it takes skill to trace particles like 「が・は・を・に」 (ga, wa, o, ni) and the subjects that Japanese so often omits.

Depending on a child's hearing situation, when there are few chances to encounter this kind of complex Japanese naturally, mastery tends to take more time.

Examples of stumbling points (complex sentences)

• Twisting an adnominal modifier: 「犬が 追いかけた 猫」 (inu ga oikaketa neko, "the cat that the dog chased") may be read as if it were 「犬が 猫を…」 ("the dog … the cat"), with who did what to whom swapped around.
• Mixing up particles: skipping or confusing 「が・を・に・は」 (ga, o, ni, wa) swaps the subject and the object.
• Losing track of the subject: as a sentence grows long, it becomes easy to lose track of "who the current subject is."

Japanese Sign Language and Japanese are different languages

What we must not forget here is that Japanese Sign Language (日本手話) has a grammar of its own. The use of space, simultaneity, classifiers (CL), non-manual signals such as facial expression and gaze, topic-comment structure, and so on—Japanese Sign Language does not map one-to-one onto Japanese word order or the way Japanese builds complex sentences.

In other words, even for a child whose signing has grown richly, reading and writing complex sentences in Japanese is the challenge of "learning the structure of a second language." Put the other way round, using a rich foundation of sign language and consciously bridging over to how Japanese sentences are built (a bilingual, bicultural perspective) becomes a great strength.

That is why we want to grow the "skeleton of the sentence"

Sentence structure generally develops in the order simple → compound → complex. Keeping this order in mind, and watching which stage a child is at now as you build up, keeps things manageable.

Growing sentence structure consciously, in small steps. This becomes the foundation for reading, for writing, and for learning as a whole. Once the skeleton of the sentence becomes visible, children can start to "read by breaking down" even the long sentences in textbooks and exams.

Hints for teaching and support (in general terms)

The best method differs from setting to setting, but here are some approaches generally considered effective, sorted by stage.

At the simple-sentence stage

• Using short sentences, first make the subject and predicate clear. Make "who" and "did what" visible by colour-coding or by position.

At the compound-sentence stage

• Read the two equal clauses by dividing them at the break. Show "this far is the first one, from here is the second one."

At the complex-sentence stage

• Show the nesting with a diagram. Connect "which clause describes which noun or which clause" with lines or arrows.
• Handle the connective words (〜とき -toki, 〜ので -node, 〜ば -ba) carefully, one at a time.

What matters throughout

• Grasp the meaning in sign language first, then bridge over to the Japanese form (meaning → form, in that order).
• Build up without strain, matching each child's actual situation.

Common stumbling points and questions

Q. Is every sentence joined by 「〜し、」 (-shi,) a compound sentence?

A. If they stand side by side as equals, yes, it is compound. If one is subordinate—expressing a reason, condition and so on—it becomes complex. You tell them apart not just by the way they join, but by "equal, or nested."

Q. Can compound and complex mix?

A. Yes. In long sentences, a nested part (complex) is often contained within a part that stands side by side (compound).

Q. Is a long sentence with lots of modifiers a complex sentence?

A. No. No matter how many modifiers there are, if there is one subject-predicate pair, it is a simple sentence. You tell them apart by "the number of subject-predicate relations."

Mini dictionary of grammar terms

Summary

Sentences come in three kinds: the simple sentence, with one subject-predicate pair; the compound sentence, with clauses set side by side as equals; and the complex sentence, with a clause nested inside another. The knack for telling them apart: "do they stand side by side as equals (compound), or has one become part of the other (complex)?"

In deaf education, mastering complex sentences in particular is a big mountain to climb. Using the rich power of Japanese Sign Language as a foundation, we want to grow the skeleton of the sentence consciously, from simple to complex. That becomes the foundation that supports children's Japanese-language ability, and, in turn, their ability to learn.