The English translation, who's meaning is as close as possible to the meaning of the German verb *wiedererkennen* would be

> re-recognize

> Einen Zauberer muss man **wieder**erkennen.  
>
> A magician must be **re**-recognizable.  
> <sup>Ein Zauberer muss **wieder**erkennbar sein.</sup>  
> You need to be able to **re**-recognize a magician.   
> <sup>Man muss einen Zauberer **wieder**erkennen können.</sup>

But this is unusual in English. The german sentence means: Once you have learned what a magician looks like, you need to be able to recognize him later **again.**

Another issue is, that the grammatical construction used in the German sentence can't be used in English. I gave you two possible English translations and their back-translations into German. All Sentences mean pretty the same.

The prefix *wieder-* means *again.* It means, that something, that already has happened before, happens again.

> Wir müssen den alten Zustand **wieder**herstellen.  
> We need to **re**store the old state. (literal: We need to **re**-produce the old state.)  
>
> Herbert musste nach einem Herzinfarkt **wieder**belebt werden.  
> Herbert had to be **re**animated after a heart attack.  
>
> Ich freue mich, dich **wieder**zusehen.  
> I'm happy to see you **again.** (literal: I'm happy to **re**-see you.)
>
> Herr Gruber wurde als Präsident des Schachklubs **wieder**gewählt.  
> Mr. Gruber was **re**-elected as president of the chess club.

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What makes re-recognize so weird in English is the fact, that **re**cognize already contains this *re-* prefix. The word *recognize* came into English from the French language, which had borrowed it from old Latin.

Latin ***re**cognoscere* is composed from *re-* (again) and *cognoscere* = to know, to get to know. So the origin meaning of English *recognize* is *to re-know.* And this meaning is still contained in the meaning of the English word. So, in English it makes not much sense to say *to re-re-know.* How can you repeat something that already is a repetition? This makes no sense.

But the German verb *erkennen* does not contain this repetitive meaning. The German verb *kennen* also means *to know*, similar to the latin word *cognoscere,* but the German prefix *er-* is not related to any repetition. The prefix *er-*, that you often see in German verbs means, that something has come to an end successfully. So, the original meaning of the German verb *erkennen* was not *»I re-know it«* but *»I have successfully learned in the past what it looks/sounds/feels like, and now I use this knowledge to identify it«.*