Ediff provides a nice visual interface to diff. ;;;Comparing and patching files is easy with ediff when you can see the screen. This module provides Emacspeak extensions to work fluently with ediff. Try it out, it’s an excellent example of why Emacspeak is better than a traditional screenreader. This module was originally written to interface to the old ediff.el bundled with GNU Emacs 19.28 and earlier. It has been updated to work with the newer and much larger ediff system found in Emacs 19.29 and later.
When using under modern versions of Emacs, I recommend setting (setq ediff-window-setup-function ’ediff-setup-windows-plain) so that Emacs always displays Ediff windows in a single frame.