Facebook has been spreading voice messaging throughout its mobile apps for awhile, but it's clear the Palo Alto crew is no longer happy leaving interaction to canned speeches. Following a quiet rollout of live voice calls to Facebook Messenger earlier in the year, a version 5.5 update to Facebook's core iOS app is giving social networkers a similar chance to talk to each other for free. The only stipulations are that users have the bandwidth to burn and live in either the US or Canada. Otherwise, the interface and functionality are dead ringers for the Messenger equivalents we tried in January. There's still no word on when full voice calls will reach Android or other platforms, although they typically get feature parity before too long.