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 8:12-13
12
Were they ashamed when they had committed abomination? nay, they were not at all ashamed, neither could they blush: therefore shall they fall among those who fall; in the time of their visitation they shall be cast down, says Yahweh.
13
I will utterly consume them, says Yahweh: no grapes shall be on the vine, nor figs on the fig tree, and the leaf shall fade; and [the things that] I have given them shall pass away from them.
