Joshua 6:1-27 says Joshua commanded the Jewish people to circle Jericho for seven days and to "not shout nor let your voice be heard, neither shall any word proceed out of your mouth, until the day I bid you shout; then you shall shout." Josh. 6:10. Was keeping a million men, women, and children silent a miracle, or was it evidence that that generation was just incredibly disciplined? Did Joshua command them to do this because G-d wanted it, or did he have other reasons? What might those reasons be?
Ralbag explains that the reason for the silence was so the inhabitants not hear them. Thus, presumably, they could speak quietly, and the "וְלֹא יֵצֵא מִפִּיכֶם דָּבָר" was overly emphatic in order to make sure they didn't speak loudly. (Note that that command to be quiet was not noted as having been fulfilled, and I have no reason to think that the entire crowd was perfectly silent. Note also (verse 3) that the only people right near the city were the soldiers and kohanim.)