The mode line normally contains the name of the current major mode, in parentheses. This mode has no mode-specific redefinitions or variable settings, so that each Emacs command behaves in its most general manner, and each option is in its default state. For editing any specific type of text, such as Lisp code or English text, you should switch to the appropriate major mode, such as C mode or Text mode. Selecting a major mode changes the meanings of a few keys to become more specifically adapted to the language being edited. In addition, the commands which handle comments use the mode to determine how comments are to be delimited.
Many major modes redefine the syntactical properties of characters appearing in the buffer.