If you're doing this on Linux, you get IPC-related (or worse, process-creation-related) latency. This is not a problem for i.e. occasional weather announcements

If you're doing this on Linux, you get IPC-related (or worse, process-creation-related) latency. This is not a problem for i.e. occasional weather announcements, but is a big issue when . creating things for the blind. If the speech synthesizer speaks each time you press a key, and you generally need to know what it said to. decide if you want to scroll further or open the focused item, every bit of latency matters. That's one of the reasons why blind people prefer robotic-sounding speech synthesizers; they're usually less CPU-intensive, which increases responsiveness. If the device you're developing for uses some proprietary firmware, a custom module might not even be an option.