YOU SAID:

How, do, you, know, who, said, what?

INTO JAPANESE

誰が何を言ったのか、どうやって知ったのですか?

BACK INTO ENGLISH

How did you know who said what?

INTO JAPANESE

誰が何を言ったかどうやって分かったのですか?

BACK INTO ENGLISH

How did you know who said what?