http://www.physorg.com/news154180635.html
Researchers have modeled the human mental lexicon as consisting of words that cannot be separated from other words, which may explain why words have many associations, a feature which helps us communicate.
When you hear the word “planet,” do you automatically think of the word’s literal definition, or of other words, such as “Earth,” “space,” “Mars,” etc.?
Especially when used in sentences, words tend to conjure up similar words automatically. Further, human beings’ ability to draw associations and inferences between words may explain why we’re generally able to communicate complex ideas with each other quite clearly using a limited number of words.