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To be understood.
That is the primary and most important purpose of words, or generally, of communication. People say things to be heard and be understood. To say differently is to cheat one's self---it defeats the very purpose of words.
However, things are not as clear cut. There are things such as noises and gestures and contexts and preconceived notions which ALTER, or worse, DISTORT the intended meaning of words being heard. There is this philosophical concept called LANGUAGE GAME which should be used simultaneously by the parties communicating, or simply people conversing, in order to UNDERSTAND each other.
Take the word "wicked" as an example. To some, it may connote negatively. "You're wicked as a witch." Conversely, it may even be a praise, "Wow, you're wicked sick!" The point is, words are interpreted differently by different people. Ergo, one should be sure that all parties/individuals are both "playing" the same language game before he/she reacts to what was heard.
This is a common source of misunderstanding among individuals. Not everyone realizes that all individuals have more-or-less DIFFERENT language games. Basically, PROPERLY construing a meaning out of words is a bit complicated than it sounds. First and most natural, we construe the words' NATURAL and PLAIN meaning. The problem is, majority of the people [un]intentionally STOP here and refuse to go the next levels, which are the determination of the INTENT of the speaker and the evaluation of the CONTEXT surrounding the communication process. Don't worry about the jargons, these are really very simple.
The words "I love you" may sound more credible if it were not to come from a man of ill-repute. The words will also sound more sincere if they were uttered in a near-death situation than in an ordinary day. Words and their meanings are very fragile, and should be handled with due care, knowledge and responsibility.
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