Hear ye … and speak. To whom is this addressed? To Jeremiah and his disciples. The Septuagint, indeed, followed by Hitzig and Graf, read (instead of "speak ye"), "Thou shalt speak unto them," adopting one different vowel-point.
But this involves an inconsistency with the first verb, and is not at all necessary, for why should we suppose Jeremiah to have been completely isolated? If the prophet had well-wishers even among the princes, it stands to reason that he must have had more pronounced adherents in the classes less influenced by the prejudices of society.