Some things are just impossible to translate without losing Much of the intended meaning, even with a human translator. Although this has nothing to do specifically with Japanese, but for translations in general.

Take for example sentences that has a play on words in the sentence. Apparently when we translate it into another language the words are different and couldn't be "played" on.


Words often have multiple interpretations or meanings, thus translation is not simply a function `f(x) = y` but `f(x) = (y<sup>1</sup> or y<sup>2</sup> or y<sup>3</sup>.. y<sup>n</sup>)`


Basically, the computer can understand all the options but there's no way it could *choose the correct one*. Two different people saying the same sentence, would have meant different things altogether but how is the computer to know that? 


As an example, the input 「僕が知っている人は誰も来なかった。」 can mean either:

1. "Of the people I know, none came."

1. "People came but, there weren't any of the people I know."

The computer does not have enough *context* to choose the right one.

Another example: by examining the input 「主人公の猫」, the computer can understand that the input has two meanings:

1. The protagonist's cat.

1. The protagonist cat (the cat, which is the protagnoist).

Yet, the computer does not have enough *context* to choose the right one.