Thanks for sharing this speech synthesizing project !
I tried it with my Littlebits Arduino Leonardo, but it did not work....
I suppose the talkie library is not suitable for the Arduino Leonardo, the hardware setup is different.
It really works nice with an arduino Uno, see this video, where I connected the Synth speaker to output 3 via a proto bit:
There was also a small error in the program file, you need to declare the sentence files with "const uint8_t" instead of "uint8_t". This needs to be done when you are using the most recent compiler, else you get an error and compiling is halted...