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.
Hosea 11:9-10
9
I will not execute the fierceness of my anger. I will not return to destroy Ephraim: for I am God, and not man; the Holy One in the midst of you; and I will not come in wrath.
10
They will walk after Yahweh, who will roar like a lion; for he will roar, and the children will come trembling from the west.