I was reading this article on Japanese numerals and I first encountered the whole On reading/Kun reading thing, with an additional column on "Preferred reading," which was almost always the On reading.
Do native Japanese speakers know both readings for every Kanji? What influence does this have on the language? What is the use and application of this knowledge? Should I bother learning the non-preferred reading?
Do native Japanese know both readings for every Kanji?
As much has every Roman knew latin. Some kanji have a
What influence does this have on the language?
Consider the characters 大,人, and 気:
now combine those:
you see, context-sensitive choice of readings.
Should I bother learning the non-preferred reading?
Should you encounter the character in an unfamiliar combination with another character, you'll have to exhaust every possible reading in a Japanese dictionary to either find it, find that the dictionary is insufficient or that you lack another reading, in which case you must consult a separate character dictionary.
Everyone has answered this really well, but I'd like to add some points that I wish someone had told me when I began learning.
The On-yomi is taken from the original Chinese reading of the kanji, and the Kun-yomi is the Japanese reading that has "adopted" the kanji, so to speak. As a general rule, if the kanji is by itself, (as in, it is not attached to other kanji, just hiragana) it generally takes on the Kun-yomi; if the kanji is part of a compound, it (and the other half of the compound) takes on its On-yomi.
Should I bother learning the non-preferred reading?
The answer is "yes". It's the difference between guessing the meaning of a word and being able to read it out loud. That may not sound like much, but it's absolutely essential.
For example: 食べる is pronounced with its Kun-yomi, たべる. 事 on its own is generally pronounced こと, which is the Kun-yomi. If you combine them 食事, they're both read with their On-yomi: しょくじ
Again, that's very generalized and not always the case, but it's the rule rather than the exception.
Regarding on'yomi, English has a very similar counterpart. You mentioned numbers, so consider the following:
Just like in English, the more of these roots (on) that know in Japanese, the easier it will be for you to understand and create new words. Often multiple on readings are generally grouped with other on readings to create a word. In this sense, they are similar to roots.
Do native Japanese know both readings for every Kanji?
Japanese is a citizenship. It can be obtained or lost. There is no correlation between citizenship and linguistic ability. If I am guessing your intent, then you likely mean "native speakers of Japanese".
And to answer the question: a native speaker of Japanese does not know all on and kun readings for every kanji. However, they will know most of all common ones and likely know a few uncommon ones as well.
What influence does this have on the language?
For the most part, loanwords.
What is the use and application of this knowledge?
A wider vocabulary.
Should I bother learning the non-preferred reading?
Absolutely. But why do you say "non-preferred"?
With Japanese numbers, yes, you must know both/all readings; it is important to be able to tell 「[九人]{きゅうにん}」 from 「[九時]{くじ}」 from 「[九]{ここの}つ」.
That highly depends if you learn only Kanji or if you learn Japanese (so Kanji + Vocabulary)
For Example nearly every kun-reading of most Kanji will be covered in Vocabulary anyway,
So you may learn the Kanji 食 with its kun-reading 食べる, but when you learn Vocabulary you will learn for sure the word 食べる anyway.
I personally learn only kun-readings when learning kanji if the kun-reading is not going to be learned in my vocabulary learning anyway.
You can do the same for on-reading and then not much is left anyway because nearly every on-reading is used in a word
I would say knowing the Readings of a Kanji is important, but its more important to do proper vocabulary learning as you will learn the readings of the Kanji too.
Best example for me was 飛行機, i can only remember the on-readings of those Kanji because i know the word 「ひこうき」 and it was one of the first words i learned.
When i was learning the On-Readings of those Kanji seperatly it was hard for me to remember them, my brain just dont allow me to remember every on-reading of every Kanji (even if i try hard), but thanks to the vocabulary that uses the Kanji i can remember them.
To actually know if the used reading is on- or kun-reading is more important!
So if you see a word for example 飛行機 (ひこうき) it is important to know if the readings used in this word are on- or kun-reading.
And Kun-Readings are "Vocabulary" anyway so i dont bother learning them when learning Kanji.
So my Answer to your question:
Dont bother learning all readings perfectly. If you learn Vocabulary afterwards you can drop the kun-reading completely as they are covered there.
You should try to learn as much on-readings as possible but i tell you something.
If you see a word you never seen before, its even for japanese nearly impossible to guess which reading to use as it depends on so incredible many things.
If you know the Word (written with Kanji), you know how to read it. If you dont know the word, you can just "guess" the readings and meanings, but that doesnt help you really. In the end you have to lookup unkown words in dictionary and you will see the reading then.
For me personally when learning Kanji the "meaning" of the Kanji and the way to write it (writing is veeery important to remember the Kanji correctly), i try to drop as many readings as possible as they are covered in vocabulary anyway.
If you want to become an Kanji Master knowing all readings, i recommend you to wait for that until you learned Japanese, if you are able to read/speak Japanese you know already most of kun-readings and on-readings so you only have to learn a very little then.
BenderRodriguez9's explanation is my absolute favorite! I edited to make it easier to read.
Here’s my example. Imagine if English were written with Kanji.
English has native Germanic words, as well as borrowings from Greek and Latin. For example, English has water, but also aqua (Latin) and hydro (Greek).
So in English's imaginary kanji system, 水 would have the kun’yomi “water” and the on’yomi “aqua” and “hydro”.
Then native English speakers figure out which reading for 水 is intended in a given context, based off of your pre-existing vocabulary:
The 水rium is powered 水-electrically with sea水.
Now this is a contrived sentence, sure. But you could easily figure out which reading of 水 to use in which situation, because you know that some readings just aren’t words. 水rium just can’t be “hydrorium” or “waterrium”.
Native Japanese speakers do the same thing. They can use all the vocabulary they know to deduce readings.
So you just need to study vocabulary, and apply kanji to the vocabulary you know. Don’t do it the other way around.
I'm in total agreement with 白川's answer. It's difficult memorizing all the readings especially the onyomi ones because much of them are the same. At times it might get confusing. I feel it better to learn the meaning, and one of the kun/on reading. If it is a verb, I give priority to that reading. As I am still a beginner, I have barely read any Japanese yet. But like 白川 says, I'll count on the vocabulary that I come across while reading to learn the readings.
