To talk to everyone within earshot, click the chat box under the view window or just hit the RETURN key. A cursor will appear. Type whatever you wish, then send your message by hitting the RETURN key. Your words will be displayed to anyone who appears on your compass.
You can send a long-distance, private message to someone if you know his or her name. Use the Talk function described above, but type the following: /tell <Character Name>, <Message>. For example, if you want to send a greeting to your friend Foozle the Clumsy, you might type: /tell foozle the clumsy, Hi there Foozle! How are you?
You can easily keep up a conversation with a particular character no matter how far apart you may drift. First, select the character by clicking him or her in the view window or his or her dot in the compass. Then, click the Chat menu in the bottom left corner of the screen. A menu will appear. From that menu, choose "Tell to ." From that point on, everything you type will be directed at only that character. You can go back to speaking normally by using the same menu and selecting "Tell to All."
A similar function is available for easily talking with everyone in your fellowship, regardless of distance. Use the "Tell to Fellows" option.