This is an AddOn designed to translate common phrases from various languages into your own language.
When you type {{ followed by part of a phrase in the chat editbox, an auto-complete menu will appear with phrases that start with the phrase you've typed. When you select one of these, it will be added to the chat message. This phrase will then be substituted for a unique identifier before the message is sent.
When a message with one of these unique identifiers is displayed in your chat frame, the identifier will be replaced with the corresponding phrase translated into your client's current language.
Translators, please read this page before translating.
This AddOn is currently in a pre-alpha state. The code still needs to be written and the translations compiled.