הדיבור (speaking) when it is done with another can be connected with the prepositions עם, את, אל, or with the prefix ל. But האמירה (saying) can only be connected with the preposition אל or the prefix ל. And the reason for this is because when הדיבורis connected with the prepositions עם or את, the דיבור (speaking) is shared between the two speakers, both exchanging speech with each other. But this is not correct with האמירה, because of that which was explained in Rule 327.