Facebook is now adding the voice message capability in its Messenger application. To send a voice message you need to click on + button as you normally do while sending a normal message. Then you need to press the Speak button and record your message. Once you release the button the voice message will be sent to your recipient.
Facebook normally uses its Messenger application very well to experiment different new features before rolling it out to the main application. There are also some news about the VoIP service testing on Messenger application in some parts of Canada. Last month Facebook also introduced the standalone Poke application which lets you send short text, pics and video messages. The messages sent via Poke expire in one to ten seconds depending on your setting.