Newsflash! World of Warcraft is what's called an MMO or massively multiplayer online game. What this means is that you're constantly playing with other people, and a lot of them. And since you're playing with them, you're probably going to want to be able to communicate with them. Though this may seem like basic stuff, WoW has a number of different communication tools and they may not all be evident to the new player. (Please don't ask me how long it took me to figure out how to use chat channels. Because, uh, I don't remember. Let's go with that.)
To start, most of the chat commands are typed into the game prefaced with a slash -- though just hitting enter will remember what type of chat command you last used and assume you want to keep speaking in the same way.
So what are you waiting for? Let's get talking.
If you specifically want to talk to players who are in the immediate vicinity of your character, you have two options: say (/say or /s) and yell (/yell or /y). These two types of chat are pretty much exactly like their real-life counterparts and both, by default, will appear as a speech bubble over your character's head as well as in everyone's chat windows. If you want to talk to people very close to your character, using say will work. And if you want to talk to people who aren't quite as nearby (but are still in the area), using yell will work. You'll frequently find both of these used in bustling public areas -- say, yelling to see if any nearby rogue can open a lockbox for you.
To use either command, hit enter and then type /s or /y followed by a space, your message, and then enter one last time to send your words out to those around you. If you've just used /s or /y, hitting enter will automatically assume you want to use the same again, so you'll just need to hit enter, type your message, and then hit enter again to send it.
If you want to communicate something that doesn't quite fit into words, an emote may be what you're looking for. Instead of showing up as text in a chat bubble, an emote is an action your character performs, accompanied by an animation. Beyond just being fun, emotes can be a handy way to communicate with players of the opposite faction, who don't speak your language (and will see says and yells as gibberish). There are lots of options, so check out the full list of emotes to see what's available. Like other chat commands, just type /emotename (where emote name is the name of the emote) and then hit enter to use it. For many emotes, you can also do /emotename playername and then enter to target the emote at playername.
Most of these are just what they sound like, but try them out and see which ones you like best! Some, like /silly, even have multiple options. And if the built-in emotes aren't enough for you, you can make your own emotes by typing /e or /emote and then what you want to emote.
If you want to talk to someone (or someones) in private, saying, yelling, or emoting won't do because everyone can see them. To talk to just one person, you'll want to whisper to them (/whisper or /w followed by their name). And to reply to someone who's just whispered you, you'll want to reply (/reply or /r, which doesn't have to be followed by their name). To talk to members of a party you've joined, you'll want to use party chat (/party or /p). To talk to members of a raid you've joined, you'll want to use raid chat (/raid or /ra). And to talk to other members of your guild, you'll want to use guild chat (/guild or /g).
If you want to talk to a specific group of people who aren't in your raid, party, or guild, you can create a chat channel for all of you to use together. To do so, just type /join channelname, where "channelname" is the name of the chat channel you wish to create. Like all of the game's chat channels (more on those in a minute), it will be assigned a number and you can speak on it using either /5, where 5 is the number the channel is, or /channelname. For your friends to join you, just have them type /join channelname as well. The game will remember the channels you were previously in and automatically join them when you log on.
Talk to (almost) everyone
There are a number of chat channels that everyone is automatically added to when they start the game. These are:
General chat (/1): Seen by everyone within the zone. For, as the name suggests, any kind of chat.
Trade chat (/2): Only available in major cities, trade chat is for the discussion of buying and selling. However, because talking on trade is visible in all major cities (while other channels are restricted by zone), it often becomes a boisterous general chat channel.
Local defense (/3): This channel is specifically for the defense of the zone. A message will go out on this channel if a PvP-flagged NPC in the zone has been killed and players coordinating defense can talk here.
Looking for group (/4): This channel is specifically for any players looking for groups within a specific zone, though a lot of this chat spills over into the (often more populated) general and trade chat channels.
Don't like any of these channels? Just type in /leave channel and hit enter to leave it. For example, you'd type /leave 1 or /leave general and then enter to leave general chat. Left a channel but decided you want it back? Just type /join channel, like /join general to go back. Note that if you leave and go back, the numbers we've listed above will have shuffled around: WoW automatically numbers channels based on the order in which you joined them.
Just because you can say it doesn't mean you should
(i) Transmit or post any content or language which, in the sole and absolute discretion of Blizzard, is deemed to be offensive, including without limitation content or language that is unlawful, harmful, threatening, abusive, harassing, defamatory, vulgar, obscene, hateful, sexually explicit, or racially, ethnically or otherwise objectionable, nor may you use a misspelling or an alternative spelling to circumvent the content and language restrictions listed above;
(ii) Carry out any action with a disruptive effect, such as intentionally causing the Chat screen to scroll faster than other users are able to read, or setting up macros with large amounts of text that, when used, can have a disruptive effect on the normal flow of Chat;
(iii) Disrupt the normal flow of dialogue in Chat or otherwise act in a manner that negatively affects other users including without limitation posting commercial solicitations and/or advertisements for goods and services available outside of the World of Warcraft universe;
(iv) Sending repeated unsolicited or unwelcome messages to a single user or repeatedly posting similar messages in a Chat area, including without limitation continuous advertisements to sell goods or services;
(v) Communicate or post any user's personal information in the Game, or on websites or forums related to the Game, except that a user may communicate his or her own personal information in a private message directed to a single user;
(vi) Harass, threaten, stalk, embarrass or cause distress, unwanted attention or discomfort to any user of the Game;
(vii) Participate in any action that, in the sole and absolute opinion of Blizzard, results or may result in an authorized user of the Game being "scammed" or defrauded out of gold, weapons, armor, or any other items that user has earned through authorized game play in the Game;
(viii) Communicate directly with players who are playing characters aligned with the opposite faction (e.g. Horde communicating with Alliance or vice versa); or
(ix) Impersonate any real person, including without limitation any "game master" or any other Blizzard agent or employee, nor may you communicate in the Game in any way designed to make others believe that your message constitutes a server message or was otherwise posted by any Blizzard agent or employee.
So remember: play nice out there. If you run into anyone breaking these rules or just bothering you, you can report them to Blizzard by talking to a game master. But that's not an immediate fix.
If someone's bothering you in game, there are a few things you can do about it:
If you're seeing language you'd rather not see, WoW has a built-in profanity filter. Though it's turned on by default, a lot of us turn it off again. Find the option in the main menu under Interface and then Social. It's unfortunately not customizable beyond turning it on and off, but you may find that it's better than nothing.
Leave public chat channels. If you find the chatter to be more a hinderance than a help, just /leave it behind. You can always rejoin later if you miss the chatter.
If a specific person is bothering you, the game lets you ignore them with the /ignore command. Just type /ignore playername and then hit enter and you'll no longer see messages from them in public or private channels. Sometimes that's all you need for a more peaceful gameplay experience.
Just because you're a newbie doesn't mean you can't bring your A-game to World of Warcraft! Visit the WoW Rookie Guide for links to everything you need to get started as a new player, from the seven things every newbie ought to know to how to get started as a healer or as a tank.