oKAY, you can… you must! (Unit 3)
The verb-ending kana changes from a "-u" sound to an "-e" sound (e.g. ～く [-ku]、～つ [-tsu]、and ～る [-ru] become ～け [-ke]、～て [-te]、and ～れ [-re]).
In other words, these forms:
We'll start with…
Remember 禁止形 (きんしけい), "the prohibitive form?" For example, we saw:
Don't sit down!
That's used when commanding someone not to do something. With the command form, however, we're commanding the listener to do something:
For godan verbs, this just means changing the final "-u" sound to an "-e" sound, and nothing else:
座る → 座れ！
すわる → すわれ！
If you watch a particularly violent, dramatic anime, I wouldn't be surprised if you heard one of the villains yell the following during a fight or something:
Note that ichidan verbs are slightly different. We take the final ～る sound and change it to ～ろ：
食べる → 食べろ！
たべる → たべろ！
Eat all of it.
Literally: "everything / all + eat."
Note: This sounds like a rather forceful command.
As usual, our Group III verbs are irregular:
する → しろ
来る (くる) → 来い (こい)
We'll talk more about uses and nuances of this conjugation type in a future JLPT lesson.
There are actually several "conditional forms" in Japanese. ～ば form, which we're seeing here, is just one of them.
For godan verbs, after changing our final "-u" sound to an "-e" sound, we add ～ば：
買う → 買え- → 買えば
かう → かえ- → かえば
There are a number of different ways that this conjugation form is used. One cool use that's easy to remember is making rhetorical questions as a form of suggestion.
For example, let's say that your friend is going on and on about a video game that she wants to buy. You say:
Why don't you (just) buy it?
Literally: "if (you) buy (it)?"
There are other interesting ways ～ば form can be used, but you'll have to look forward to learning about them in future lessons.
Note that ichidan verbs are a little different: We just add ～れば to an unchanged verb stem:
食べる → 食べ- → 食べれば
たべる → たべ- → たべれば
寝る → 寝- → 寝れば
ねる → ね- → ねれば
Finally, we have our irregular forms:
する → すれば
来る (くる) → 来れば (くれば)
One cool thing you may notice right off the bat is that 可能形 (かのうけい // possibility form) is the conjugated the same as 受身形 (うけみけい // passive form) for ichidan verbs.
So, depending on the context, 食べられる (たべられる) could mean "be eaten" or "can eat."
Compare the following two sentences:
さかな が とり に たべられた。
The fish was eaten by a bird.
Literally: "fish + が + bird + に + was eaten."
Here is the process we're going through to conjugate the verb above:
食べる → 食べ- → 食べられる → 食べられた
たべる → たべ- → たべられる → たべられた
からい もの たべられない。
I can't eat spicy food.
Literally: "spicy + thing + cannot eat."
Here is how we're forming that negative plain tense of the possibility form, which I've also heard referred to as the "potential form," by the way:
食べる → 食べ- → 食べられる → 食べられない
たべる → たべ- → たべられる → たべられない
If you're wondering why we can just replace ～る with ～た to form the plain past tense and ～る with ～ない to form the negative plain (present) tense, the reason is that possibility form, passive form, and causative form all conjugate like ichidan verbs. ← If that is an altogether confusing sentence, just wait to worry about this when you hit these lessons in our JLPT N4 course.
On another note, although it's technically incorrect, you'll sometimes hear people leaving out the additional ら in the possibility form of certain ichidan verbs, particularly in informal speech. So, although this is correct:
食べる → 食べ- → 食べられる
たべる → たべ- → たべられる
…you'll often hear people just say:
食べる → 食べ- → 食べれる
たべる → たべ- → たべれる
Anyway, moving on…
For the possibility form of godan verbs, after changing our final "-u" sound to an "-e" sound, we add ～る：
買う → 買え- → 買える
かう → かえ- → かえる
Here's a sentence that you might find useful, one that is using two of our possibility-form verbs:
かんじ は よめる けど かけない。
I can read kanji, but I can't write them.
Literally: "kanji + は + can read + but + can't write."
Did you catch why we wrote 書けない (かけない) for "can't write?" Like I mentioned earlier, possibility-form verbs conjugate like ichidan verbs, so:
書く → 書け- → 書ける → 書けない
かく → かけ- → かける → かけない
If we pretend that 書ける (かける) is an ichidan verb, then, like other ichidan verbs, that would mean that the stem is unchanged when conjugating it into negative plain form (or any form, really). Note the similarities between the conjugations of 食べない (たべない // don't eat) and 書けない (かけない // can't write):
食べる → 食べ- → 食べない
たべる → たべ- → たべない
to eat → → don't eat
書ける → 書け- → 書けない
かける → かけ- → かけない
can write → → can't write
As for our irregular verbs, 来られる (こられる) is the same in both possibility and passive forms… though you'll probably hear the possibility form used more often, since "can/cannot come" is a pretty common thing to say.
The verb する, however, is completely different for possibility form:
する → できる
Sometimes you'll see it written in kanji: 出来る (できる // can do).
Are these lessons making your head spin so far?
I think that would be normal, since we're basically speeding through conjugations that most don't learn until they're hundreds of hours into their studies.
I wouldn't worry about being confused at this point. I would, however, look forward to reading all of this someday in the future and feeling that you understand it all!