His father, who knows schoolboy German, translated the letter...

[sunsunmoon]

Baltic Sea letter in a bottle found 24 years later - Yahoo! News
His father, who knows schoolboy German, translated the letter, carefully wrapped in cellophane and sealed by a medical bandage.


I don't understand what knows schoolboy German means. Isn't this sentence correct without the "schoolboy"?

[Rover_KE]

He knew the language at a beginners' level.

You could say basic German.

Rover

[BobK]

He knew the language at a beginners' level.

You could say basic German.

Rover

... but maybe not even that much. 'Schoolboy <language>' is both basic, perhaps partially understood, learnt by rote, and long-forgotten.

b