One of the most important applications of the conditionals is "must" and "must not".
漢字 to learn this week: 灰、区、浴、勇、銭、墓、批、具、寿 、返、片、恐、刻、改、研
The word "must" can be made with several double negative combinations. The exact nuances are not the same, but the differences lie in speech style.
| ～なくては||だめ (casual), いけない (neutral), ならない (formal), なるまい (formal/ stiff)|
|～ないと||だめ (casual), いけない (neutral), ならない (formal), なるまい (formal/ stiff)|
|～なければ||だめ (casual), いけない (neutral), ならない (formal), なるまい (formal/ stiff)|
|～ねば||だめ (casual), いけない (neutral), ならない (formal), なるまい (formal/ stiff)|
Notes: Conjugate ある to あらねば for method 4. Polite speech forms are created as normal. Lastly, いけない may be seen as ゆけない, but this is more expected of in writing.
～ない follows the 未然形. Use だ with these to show that something must be. Use adjectives with these to show that a state that must be.
は emphasizes the negative here. だめ is a 形容動詞 meaning "useless". いけない is similar to "bad/not good". ならない shows obligation by showing that things won't happen if you don't. まい here is the negative volitional and is formal, stiff, and old-fashioned. ～ねば is actually ～ぬ (older negative ending) + the particle ば.
In reality speakers are lazy. Here is how "must" can be shortened.
|～なくては → ～なくちゃ|
|～なければ → ～なきゃ|
| ～なければ → ～なけりゃ|
Usage Note: ～なくちゃto some is somewhat kiddish, but ～なきゃ isn't deemed so. Tone of voice has a lot to do with it.
Remember, ～ない can also be seen as ～ん,～ぬ, and ～ねー. ～ん is either dialectical or casual in this context. ～ぬ is old-fashioned and is, as mentioned above, seen in the combination ～ねば. ～ねー is typically viewed as slang/vulgar though being a common sound change in most East Japanese dialects. Last but not least, don't forget that the polite forms still apply here.
You must hurry.
Children must go to bed early.
明日までに報告書を書かないとだめだよ。(Casual yet serious)
You have to write a report by tomorrow!
I have to return the book.
You have to die.
It's a matter of life or death, so you must take measures.
We must avoid an excess of waste.
I've got to go.
It's because I have to play with my little brother.
You have to drink water every day.
I have to catch the boat.
I have to go buy the new book.
Word Note: ｛その・あの｝新しい本 may be more natural in many contexts than 新刊, which can also be interpreted as "new publication". Nevertheless, 新刊 is still a commonly used word.
You have to pass no matter what.
From 蒼氓 by 石川達三.
Base Note: The old みぜんけい of する, せ-, must be used with ～ぬ.
Variant Note: There are several important notes about the above sentence. The ～ね in せねば is contracted to ～ん and ～ない in ならない becomes → ～んね, which would be realized today in Modern Japanese as the casual ～んねー such as in 分かんねー・分かんない.
Important Dialectical Variants
Sometimes "must" is expressed completely differently in other dialects. The most common dialect pattern is "未然形 ＋なあかんで". You can also see ～ねば contracted to ～にゃ in Western Japanese Dialects.
いけない is very sensitive in respect to dialect. Below is a chart of the most common variations you may encounter.
I have to buy a one-way ticket.
I have to sing.
せにゃならん ＝ しなければならない
せないかん ＝ しなければならない
Note: The last is also a Western Japanese dialect example. Here, we see a rare example of ～ない following the old 未然形 of the verb する, せ-, and あかん contracted as かん.
"Must not" is made by changing a verb into the て形, adding は, and following it with one of the three endings like before. You may choose と or ば. Of course, you must attach them correctly to the 終止形 and 已然形 of the verb respectively and recognize their nuances. Again, the same endings apply.
You must not come together (with us/me/them).
Children must not drink sake.
You must not run in the middle of the house!
It must not be a used car.
You must not use your cell phone.
You must not do that!
You must not eat that!
You simply have to forget.
You must not think so.
~If I go, it'll be bad.
In slang ～ては contracts to ～ちゃ and ～では contracts to じゃ. This contraction is considered kiddish to some speakers, but when seen in ～ちゃいけない like the final example, such feelings towards the pattern away. However, the first two examples do sound less adult like because of ～だめ following it.
You can't die!
You can't be late!
You mustn't look back again.
From 海辺のカフカ by 村上春樹.
1. What are the four possible endings you can choose from for the phrase "must not"?
2. What are the contractions for -ては and -では in slang for "must not"?
3. How many combinations are there to say "must''?
Translate to Japanese (5-8)
4. I have to go to school today. Then, I have to go home and clean the house.
5. How about talking to your parents more?
Translate into English (9-10)