Speak
Like "say," the word "speak" refers to thoughts and feelings moving from our more internal spiritual levels to our more external ones -- and ultimately from the Lord, who is in a sense the most internal spiritual level of all. This is generally called "influx" and "perception" in the Writings, meaning they are thoughts and feelings that flow in in a complete way from the Lord, rather than being things we have to think about and figure out. On a number of occasions "speak" and "say" are used together; in these cases "speak" refers more to intellectual instruction in matters of thought and "say" refers more to feelings and affections that flow in directly.
Jeremiah 25:7-9
7
Yet you have not listened to me, says Yahweh; that you may provoke me to anger with the work of your hands to your own hurt.
8
Therefore thus says Yahweh of Armies: Because you have not heard my words,
9
behold, I will send and take all the families of the north, says Yahweh, and [I will send] to Nebuchadnezzar the king of Babylon, my servant, and will bring them against this land, and against its inhabitants, and against all these nations around; and I will utterly destroy them, and make them an astonishment, and a hissing, and perpetual desolations.
