jEdit supports "Edit modes". The edit mode of the current buffer deteremines the coloring of the words in the buffer. You can learn about edit modes from the jEdit user guide (available from the Help menu), or:
http://www.jedit.org/users-guide/modes.html
for information about using edit modes, and:
http://www.jedit.org/users-guide/writing-modes-part.html
for information about writing edit modes (or customizing existing ones).