Yomi Confusion
If a word has multiple kun-yomi, the okurigana usually make it clear which yomi you should choose. (If I've lost you here, see "okurigana" in the "How Kanji Combine in Compounds" section of the glossary.) That's true in these words:
明るい (あかるい: bright, cheerful)
明ける (あける: to become bright)
明らか (あきらか: obvious)
明く (あく: to open; be empty)
As you can see, each yomi has a different meaning, so the okurigana make a world of difference.
Pairs of Words with Unhelpful Okurigana
Unfortunately, okurigana are not always so helpful! In essays 1639 (怒: anger) and 1432 (辛: spicy), I spend considerable time exploring pairs of words in which the okurigana tell us nothing about the yomi. For instance, there are these:
辛い
(からい: spicy; tough on someone)
(つらい: painful, bitter, heartbreaking)
Clearly, these words are quite different, and it's important to know which 辛い you're seeing. Context can make this apparent, but when that's not the case, people often opt to write the whole word in hiragana.
Here's the key pair of look-alikes from essay 1639:
怒る
(おこる: (1) to get angry; (2) tell someone off; scold)
(いかる: (1) to get angry; (2) be angular; be square)
Essay 1639 presents situations in which it's okay to use these interchangeably, as well as instances in which one works better than the other.
This issue also crops up in essay 1188 (屈: to bend) with the following word:
屈める
(かがめる: to stoop, bend)
(こごめる: to stoop, bend)
Both yomi are non-Joyo. As I note in the essay, few people use こごめる, so if you face this choice, opt for かがめる.
Essay 1625 on 摘 (to pick) presents another set:
摘む
(つむ: to pluck; pick (esp. flowers); trim; gather)
(つまむ: to pinch; hold; pick up)
Looking at 摘む, we don't know whether to read it as つむ or つまむ. They're both transitive verbs, so context won't help. However, つむ is the only Joyo yomi of the two; people usually write つまむ in hiragana to avoid yomi confusion.
I list two more pairs in Crazy for Kanji, page 40:
入る
(はいる: to enter)
(いる: to enter)
注ぐ
(つぐ: to pour liquid), a non-Joyo yomi
(そそぐ: to pour, used for anything from pouring liquid to "pouring" one's attention into a task)
And that's not all! I've also stumbled across these:
突く
(つく: (1) to prick; stab; (2) poke; prod; push; thrust; nudge; hit; (3) use (a cane); prop oneself up with; to press against (the floor, etc.); (4) attack; (5) brave (the rain, etc.))
(つつく: (1) to poke (repeatedly, lightly); nudge; (2) peck at (food); pick at; (3) peck at (someone's faults, etc.); (4) egg on)
Oh, no! The definitions of つつく seem to be a catalogue of my faults! Anyway, because you would most certainly want to distinguish these two yomi (e.g., differentiating between stabbing someone and harassing them about their faults), people tend to write つつく (a non-Joyo yomi) in hiragana.
Dirt Brings On Yomi Confusion
Essay 1031 on 汚 (dirty) includes no fewer than three pairs with unhelpful okurigana! What is it about dirt that prompts yomi confusion?
Consider, for instance, these words:
汚す
(よごす: to pollute; contaminate; make dirty; stain)
(けがす: to disgrace, dishonor, defile)
汚れる
(よごれる: to get dirty, literally)
(けがれる: to get dirty, figuratively; be violated; be corrupted; be polluted; be stained)
The first set is transitive, and the second set intransitive. But that's the less important distinction to make. With these pairs, be mindful of the following pattern:
• よごす and よごれる are for physical dirt (e.g., when water is contaminated).
• けがす and けがれる are for people with "moral dirt" (e.g., besmirched reputations).
There are a few exceptions; that is, some words muddy the issue! But on the whole, if you associate よご- with physical dirt and けが- with figurative filth, you should be in good shape.
In passing, the essay also touches on this pair of verbs:
雪ぐ (すすぐ: to wipe out (disgrace))
雪ぐ (そそぐ: to wipe out (disgrace))
Because the definitions are identical in this case, there's less room for confusion. By the way, both yomi are non-Joyo. Most of us are more familiar with 雪 as ゆき (snow).
Verbs with Three Possible Kun-Yomi!
As if pairs of possible yomi weren't enough, I've found words with as many as three kun-yomi! Here's one example:
開ける
(あける: (1) to open (a door, etc.); unwrap; (2) open (for business, etc.))
(ひらける: (1) to become opened up; improve; (2) develop; progress; become civilized; be up-to-date; (3) be enlightened; be sensible)
(はだける: to expose; bare)
In this case, context will certainly help; あける is transitive, whereas ひらける is intransitive, and people usually write はだける in hiragana. Moreover, people use はだける solely in reference to body parts. Nevertheless, I'm a bit surprised to find 開 involved in this sort of tangle because it's closely associated with 明 (in fact, they're often interchangeable), and as we saw at the start, 明 words contain helpful okurigana. In fact, 開 also plays a part in this confusing pair:
開く
(あく: to open; be unlocked; be open for the day (e.g., a shop); be emptied; have a vacancy or vacant post)
(ひらく: to open; open in all directions like a flower or umbrella; have a large difference (e.g., in age))
In another case with three kun-yomi, the meanings again differ, though they do overlap:
凝る
(こる: to be enthusiastic about something; elaborate (on something); become stiff)
(こごる: to be frozen, be congealed; be stiff with coldness (e.g., fingers))
(しこる: to become stiff; to harden)
The first yomi yields some intriguing definitions. When I'm enthusiastic about something, the last thing I feel is stiff!
The second yomi is quite uncommon today, factoring into just one term, and only as a noun. That term is 煮凝り (にこごり: jellied fish or meat broth). Blech!
In the same vein, people rarely use the third yomi, しこる. They're familiar mainly with its noun form, しこり (stiffness; lump; unpleasant feeling). For example, a woman with a tumor in her breast might say she has a しこり in that area of her body. Furthermore, if you used an unsavory method to solve a problem, it would leave a しこり (an unpleasant feeling or a bad aftertaste) for everyone involved.
A Pair of Verbs with a Ready-Made Solution
One pair of verbs comes with a ready-made solution. That is, 掛る could be either かかる or かける. Each means "to hang," but かかる is intransitive, whereas かける is transitive. Therefore, it's preferable to use these alternative forms:
掛かる (かかる), rather than 掛る
掛ける (かける), rather than 掛る
When Conjugation Causes Yomi Confusion
Here's an instance in which conjugation can cause yomi confusion:
行く (いく: to go)
行う (おこなう: to perform, conduct oneself, carry out)
These words are distinct in every way. But the -て form is 行って in both cases. You could pronounce this either as いって and おこなって, depending on the verb intended. For kanji learners, it's no small thing to see the ultra-familiar 行って and to choose not to read it as いって. But that's the sort of challenge we signed up for when we decided to learn this language!
A Postscript
The more I write about kanji, the more unhelpful okurigana I encounter, and I always feel the urge to add to this Thematic Exploration. But doing so seems daunting if I expect myself to weave the information in seamlessly. Fortunately, I've found a solution. I'll keep a running list of new discoveries right here. I've also included some on-yomi puzzlers. Here we go:
解ける
(ほどける: to come untied), a non-Joyo yomi
(とける: to come untied; be solved, be worked out (a puzzle); be able to untie; be able to solve), a Joyo yomi that sounds much more literary than ほどける
解く
(ほどく: to untie), a non-Joyo yomi
(とく: to untie, solve), a Joyo yomi that sounds much more literary than ほどく
打つ
(うつ: to hit in general)
(ぶつ: to punch), a non-Joyo and much less common yomi
忙しい
(いそがしい: busy)
(せわしい: busy), a non-Joyo and much less common yomi
(くぼむ: to cave in; (for an object to) become depressed; to sink), a non-Joyo yomi
(へこむ: (1) to be dented; be indented; yield to; give; sink; collapse; cave in; (2) be overwhelmed; feel down; be forced to yield; be daunted), also a non-Joyo yomi
(はさむ: (1) to hold something between; (2) slam (a door on a body part); (3) insert something between; (4) face (someone or something); (5) hear or overhear something; (6) do something between appointments or events; (7) bear, conceive, nourish, harbor), which is by far the more common way to read this word
(さしはさむ: (1) to insert, inject; (2) cut in, interrupt; interject; (3) interfere, meddle; (4) bear, conceive, nourish, harbor), a non-Joyo yomi that people also represent with the less-confusing 差し挟む
(-ちゅう: X-ing right now; while X-ing; in)
(-じゅう: throughout a place; throughout a period of time)
敵
(てき: enemy)
(かたき: a person one deeply begrudges, probably for killing a loved one; rival (incl. a business rival))
(える: (1) to get, acquire, obtain, procure; (2) earn; win; (3) gain, secure), the Joyo kun-yomi of 獲
(とる: to take; catch (fish or game); capture), a non-Joyo kun-yomi