All acts of communication have a number of things in common. There is always a sender, a message and a receiver. The sender encodes a message, the receiver decodes it. The message travels along the channel, where interference may occur. The receiver provides feedback on the message to the sender.

Figure 1: the communication system

Communication can serve three purposes. They are the informative purpose, the persuasive purpose and the stimulating purpose. These purposes of communication apply to both written and oral communication. If a sender wants to inform the receiver, he will present factual information only. If the sender wants the receiver to share his opinion, his purpose becomes persuasive and he will phrase his message differently. If the sender wants the receiver to take action, his purpose becomes stimulating. Again, he will use different words and constructions to make his purpose clear.

When communicating, the sender has one of these purposes, or, frequently, a combination of them, in mind. The receiver should be able to read the communicative purpose in the message the sender has sent him.

This means a writer has to be conscious of his purpose when writing the message, no matter whether he is writing a letter of application, an e-mail message, a report or anything else.

Equally, a speaker has to be conscious of his purpose when speaking; it makes no difference whether he is speaking in a presentation, a meeting or in any form of dialogue. This is the first step in phrasing the message so that the reader reads what the writer wants him to read and the listener hears what the speaker wants him to hear.

The sender sends a message to the receiver. It is important for the receiver to understand the sender's message correctly. Therefore the sender has to keep the receiver's position in mind. With writing this means that the writer understands how the reader reads. With speaking it means the speaker understand how a listener listens. The sender has to structure his message so that the receiver easily and quickly understands what the sender is trying to say. In other words, whenever you communicate, you try to imagine how your audience will appreciate your message.

Readers have certain expectations when reading a text. For example, readers expect paragraphs dealing with one subject only, so writers must write paragraphs dealing with one subject only. Readers expect the topic sentence of a paragraph to tell them what the paragraph is about. Therefore writers must write topic sentences that tell the reader what the paragraph is about. When writers do what readers expect, written communication becomes effective.

The same goes for oral communication. For example, participants in a meeting have certain expectations. They expect fellow participants to give valuable contributions to the actual discussions. So, when speaking in a meeting, you speak in such a way that your fellow participants listen to you and, at least, correctly understand what you say. Therefore, you speak loudly and slowly and you build up your argumentation carefully and precisely. Naturally, this does not mean the other participants will also agree with you.

Likewise, an audience in a presentation expects the speaker to present worthwhile information attractively. They want to leave the presentation with the idea they have learned something. Again, as an effective speaker you bear this in mind. You realise the audience is the most important part of your presentation: you are there for the audience, the audience is not there for you.

Finally, the same applies to all dialogues. The speaker phrases his message so, that the listener knows instantly what he means. The listener reacts: the moment the listener starts speaking, he becomes the sender of a new message, and the first speaker becomes the listener/receiver. In dialogues especially, this changing of roles happens constantly.

As you have experienced yourself, in dialogues communication fails more frequently than in, for example, meetings and presentations. In dialogues the solution is simplest, too: it is easy to ask for clarification. In meetings it is comparatively easy to correct mistakes, but since people tend to concentrate better in meetings, communication failures occur less frequently. In well-prepared presentations, failures occur least frequently.