YOU SAID:

He said what she said was wrong, but she said that was wrong, so in the end they said that they were wrong about being wrong about being wrong.

INTO JAPANESE

彼は彼女が言ったことは間違っていると言ったが、彼女はそれが間違っていると言ったので、結局彼らは間違っていることについて間違っていると彼らは言った。

BACK INTO ENGLISH

He said what she said was wrong, but she said it was wrong, so in the end they said they were wrong about what was wrong.

INTO JAPANESE

彼は彼女が言ったことは間違っていると言ったが、彼女はそれが間違っていると言ったので、結局彼らは彼らが間違ったことについて間違っていると言った。

BACK INTO ENGLISH

He said what she said was wrong, but she said it was wrong, so in the end they said they were wrong about what was wrong.