Kanji composition to create vocab - how does it work?

Hello and thank you for stopping by!

As I’ve started learning a bit of grammar, the vocabulary lessons containing 2 kanji started to make me rather confused. In English when we compose two different words we do it by the same grammatical rules we use in speech so the result is consistent and predictable. However, in Japanese I can’t yet quite grasp these rules.

Let me give some quick examples:

  • If I know the word inside, I can combine it with a plethora of nouns to refer to the inside of such objects using the word the. Inside the house, inside the car, inside the book etc. Having learned (inside) I thought I would be to use it by a similar set of consistent rules, like 家の中車の中本の中 etc. Then I get the Wanikani vocab for “inside the car” and it’s 車内(しゃない). I can memorize it sure, but the fact that the kanji also have different readings now make me unsure about how to say inside the house or inside the book.
  • Thought adjectives like 小さい would empower me to describe any number of nouns, such as 小さい犬. Then I stumble upon “small plate” read as 小皿(kozara) and now I have no idea what I can even use 小さい with. Does small cat work? What about small pen? But what about a big plate? A real existential crisis!

Please tell me I’m missing the bigger picture here!

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The fact that certain things are combined into their own words doesn’t mean that the other ways of using words are invalid.

There’s no reason you can’t say 小さい皿. In fact, that’s how 小皿 is defined if you look it up in Japanese.

Usually if there’s a difference, the kunyomi version will be more colloquial, although there are exceptions.

As you get exposed to more of the language you’ll see which ways of saying things are more typical of how natives say things, but until then there’s no reason to question what you know so far.


Wait until you see 小さな.

小さい is an adjective, therefore you can describe anything with it, but 小〜 constructs are words in and of themselves.


The important thing to understand here is that 車内 is a single word; it is not two words combined according to some grammar rule you don’t know yet. This is a bit like how in English you can say something is “on top of the table” or that it is “on the tabletop”. But you don’t have to use the compound word just because it exists. Also like English, you can’t arbitrarily coin new compound words: we have desktop and tabletop and rooftop, but not chairtop – you have to say “on top of the chair”.

Japanese because of its history and Chinese influence tends I think to have more of this sort of compound word than English does.


English has a bunch of these if you think of how we use greek and latin words as suffixes and prefixes. I think it is similar to how we have the concept :droplet: and for that concept we have a word like “water” or (みず), and then also a building block for compound words like “hydro” or (スイ).


It’s been shocking to me just how much of the so-called crazy parts of Japanese are present in English too. I recently had this realization with the entire number system.


I would say instead that it’s just more obvious in Japanese because of the kanji.


Adding to it, when referring to compound ideas one should use the no particle if a compound word does not exist. If one wanted to say “food war” in Japanese, it would be (food)の(war). The word 食戟(shokugeki) from the Food Wars anime is something they invented for the show and not something anyone would ever use to literally say “food war”. What are your thoughts on this?

You can just create your own compounds and people would understand as long as they know the kanji. :man_shrugging:

Like the 腐海ふかい in Nausicaä. :slightly_smiling_face:


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