Chat Channels

Chat Channels make it easy to communicate with your party, your guild, nearby people, as well as everyone on the battlefield. With them, you can send messages to a targeted group of people to plan your strategies, talk to your group, warband, local area, or simply reminisce about old conquests and classic kills

Chat Channels are accessed via slash commands. So, if you want to talk to your guildmates in Guild Chat, type “/gu”, which will automatically change the chat buffer to reflect you are entering text into the Guild Chat channel.  /p is for yoru party chat, a change from the more typical /g in other MMO's out there.