Possibly. When using LANnouncer, text is sent to your android device via Big Talker and SmartThings and the speech processing is done within the devices text-to-speech engine itself. It’s possible you could try changing to a different TTS engine in the Android OS to see if another engine works (ie: is it just the Google TTS engine broken?). This is usually found under Settings > Accessibility (varies where under here depending on the device; mine is at Settings > Accessibility > Vision > Text-To-Speech > Preferred TTS engine).
Also, make sure that your android device hasn’t changed it’s IP address from the one you have configured in SmartThings for your LANdroid device (open LANdroid to see what it shows as your IP; in SmartThings go to My Home > Things, locate your LANdroid device and tap on it > tap the gear and check Android IP Address and Android Port ). If your IP differs, change the settings in SmartThings for your LANdroid device to match the IP and Google how to set a static IP address in your router for your LANdroid device.
If your IP is still correct and changing TTS engines doesn’t work, you might head over to the LANdroid page and ping @NWTony to see if he knows anything about the mentioned update breaking LANdroid. Android as a Speech/Alarm Device released! And Updated!
I hope this helps