Quotes are always useful for inspiration, elucidation, imagery and context. Keep a file of great quotes as you come across them; that file will soon become a robust resource to fire your imagination and add interest to a presentation or article. Brainy Quote, ThinkExist and STLyrics (Song Title Lyrics) are all good sources to aid your creativity.
Here are a few of my favorite communication quotes:
"Communication takes place in the mind of the listener, not the speaker."
"The problem with communication is the illusion that it has been accomplished."
George Bernard Shaw
"Mend your speech a little lest you mar your fortunes."