At that time Berodachbaladan, the son of Baladan, king of Babylon, sent letters and a present unto Hezekiah: for he had heard that Hezekiah had been sick. At that time Berodach-baladan - He is called Merodach-Baladan, Isaiah 39:1, and by the Septuagint, Syriac, and Arabic versions, and by several of Kennicott's and De Rossi's MSS.; and also by the Babylonian and Jerusalem Talmuds. The true reading seems to be Merodach; the מ mem and ב beth might be easily interchanged, and so produce the mistake.
Sent letters and a present - It appears that there was friendship between the king of Babylon and Hezekiah, when the latter and the Assyrians were engaged in a destructive war. The king of Babylon had not only heard of his sickness, but he had heard of the miracle; as we learn from 2 Chronicles 32:31.