Although RIM is struggling in North America, the BlackBerry continues to sell well in such markets as South Africa, Nigeria and Indonesia.
The BBM service has long been a reason for BlackBerry users to not defect to other smartphones but there are rival messaging services. There are more than 60 million BBM users worldwide.
RIM said the BBM voice update is currently available for BlackBerry smartphones running the BlackBerry 6 operating system or higher, with plans for BlackBerry 5 later. RIM's latest phones run the 7 operating system. The next version, BlackBerry 10, will come soon after a Jan. 30 launch event.