Much like てはならない
states that something ‘must not’ be done. However, this is where the similarities end. なくてはならない
is an example of a double negative in Japanese, and actually has the meaning ‘(A) must be done’, or ‘must do (A)’.
While this grammar point is usually translated as ‘must do’, the literal translation is ‘must not, not do (A)’. This double ‘not’ is where many learners have difficulties. ならない
simply means ‘cannot become’, and comes from the negative form of なる
To use this structure, simply create the negative form of a verb, and then convert ない to なく (the conjunctive form of an い-Adjective
), followed by て
. After this, は
is added, and then finally ならない
I have to get off at the next bus stop. (I must not, not do it)
Tom must give back money to Taka. (He must not, not do it)
I have to study kanji today. (I must not, not do it)
is considered to be the most formal structure out of ならない
, and だめ. It is regularly used in formal writing, or semi-formal/formal speech. いけない
(the most common variation) and だめ (the most casual variation) are also acceptable in many situations.
The ては in なくては is often shortened to ちゃ, as this is easier to say. なくちゃ
may then be followed by ならない
. However, due to ならない
being quite formal, なくちゃ
(a casual structure) will not be used with ならない
on a regular basis. It is more common to see なくちゃ
paired with いけない
, or だめ.
Because I ran a lot today, I must take a shower.
I gotta bring meat to the barbeque.
We gotta go camping before it becomes winter, right?
These casual structures are very similar to words like ‘gotta’ in English.