YOU SAID:

Knock knock who's there?

INTO JAPANESE

がノックですか。

BACK INTO ENGLISH

Is the knock.

INTO JAPANESE

ノックの音です。

BACK INTO ENGLISH

This is the sound of a knock.

INTO JAPANESE

これは、ノックの音が。

BACK INTO ENGLISH

This is a knock sound.

INTO JAPANESE

これは、ノック音が。

BACK INTO ENGLISH

This is a knock sound.