Plogue has released a free demo version of chipspeech, a vintage-style speech synthesizer which recreates the sound of famous 80's voice synthesis chips.
It features 7 different voices, each with its own characteristic timbre. It is specially tailored for musical needs – simply type in lyrics (in English or Japanese), and then play on a MIDI keyboard. It's a true synthesizer, the sound can be extensively modified for easy and expressive performances through the use of MIDI CCs or parameter automation.
chipspeech also features a circuit bending emulation, letting a user not only recreate the chaotic sound of a circuit bent TI speaking device, but also use it in a controlled, musical way.
chipspeech can work as a VST/AU/AAX/RTAS plug-in for most major sequencing audio programs and supported tracker programs. All this on both Windows and OS X operating systems.
Here's an example of chipspeech in action: http://youtu.be/SXUu2ZcuiLU