Eventually, if you are a new player, the game will send you a message showing you how to chat.
By clicking on the speech icon in the lower-left, the menu of phrases will appear. Once chosen, the pirate will say that phrase in whatever type of chat is currently selected (Local, Crew, Guild, etc.) Another way of communicating with your fellow pirates are emotes.
These are basic reactions your pirate can perform to express their emotions.
Next to the speed chat icon is the emote (head) icon.
To chat with other pirates, simply type your text into the box and click Enter. For protection of younger players, many words, including numbers, have been deemed inappropriate, but the Disney administrators do offer pirates the opportunity to request words be added to the dictionary.
The first small icon that looks like a page is where you will find the master list of movement options.