Why the name Evil-merodach Is it a title?

And why is merodach written with a lower case "m"?

PS: I came across this name from Jeremiah 52:31 of an NLT Bible
The King James Version and the English Standard Version use the name Evil-merodach, as does the New Living Translation.  Clearly, using lower-case m is not a typographical error!  However, as to why the second part of the name does not have a capital letter M, there is no explanation.

The New International Version uses the name Evil-Merodach and notes he was also called Amel-Marduk.  He was Nebuchadnezzar's successor.

History records that Nebuchadnezzar was a follower of the Babylonian gods Nabu and Marduk.

The 'Enuma Elish' describes a great clash between various gods of the Babylonian pantheon: 


  The two most important characters are the god Marduk and the goddess Tiamat. After Tiamat prepares many monsters and lesser gods to destroy the remainder of the pantheon, and a few younger gods have already failed at challenging her, Marduk offers to destroy Tiamat in return for being made highest among the gods. The other gods readily accept this offer, and Marduk becomes locked in mortal combat with Tiamat. After killing Tiamat, Marduk splits her body in two, making one half the sky and one half the earth. He makes humans from his own flesh and bone and brings order to the universe. 
  Source: http://www.sacred-texts.com/ane/stc/index.htm


The Enuma Elish is one of the oldest creation records ever discovered, likely dating to 1100 BC (Genesis, which is older, was written around 1400 BC).  

As to why older Bible translations record the king's name as Evil-merodach, no explanation is given.  But Ken Graham's fulsome answer sheds light on his character, which may account for the prefix of Evil.