これは日本語独特の表現ですって英語でなんて言うの？

To get across = to communicate the meaning of something
To make sense = to be understood
To mean something = to have significance

You can use the above sentence to express yourself . Other examples are:
"There is no direct way to translate it from Japanese to English".

If the Japanese words contained in the phrase do not have any equivalent words in English, it is impossible to have them translated.
Maybe the first thing to do would be to look for Japanese synonyms for these words.
It may be possible to find English equivalents for the synonyms.
A synonym is a word having the same or nearly the same meaning as another in the same language, as happy, joyful, elated This might help.

In conversation, you can say, "it's hard to explain this word because it has no direct English translation" or "this word only exists in the Japanese language so it's hard to explain."

This is in essence an AFFIRMATION whereby a group can show each other in this greeting and express aloud, just how committed they are to the purpose at hand.
(i've got your back :-) would be a rough interpretation.

You can say :

'There is no direct translation. It is a Japanese phrase.'
It only makes sense in Japanese and in no other language.

Sometimes some words and phrases are difficult to translate from one language to another.
In such cases, to explain this we can say:-

1. That phrase has no Japanese translation.

2. That phrase only exists in the Japanese language.

   Hope this helps!

• There is no direct translation : This describes that when you try to translate the phrase you are unable to find a perfect translation for the meaning. I.E: When you put the phrase in a translator app.
  
  • It is a unique expression : This talks about the uniqueness of the expression or phrase to show that although it can be understood through explanation, it isn't something there is an exact word or phrase for in another language.

Another option could be the following: "I can translate it but it won't make any sence in English". I promise to you most of the people know that not all proverbs can be translated.