If you'd rather actually SPEAK to your friends instead of dropping a link to an appropriate GIF on their wall, then
download Skype. I mean, use Facebook Messenger for iOS, which from today brings a feature our Amurrrican friends have been testing for the past couple of months.
The Facebook Messenger app will be updated at some point today, Zuckerberg's underlings have assured us, but Android and BlackBerry owners/sufferers (delete as appropriate) will have to stick to using the app purely for texting and IM for now.
Just in case you missed the announcement in January, it enables users to call their Facebook friends over Wi-Fi for free, and even leave voicemails if the receiver doesn't have the app. The big advantage here is obviously for iPod Touch or iPad owners, with the app effectively turning their non-phones into phones.
Y'know, unless they have Skype already downloaded... [Facebook]