Voltage Controlled Speech Synth

[Romeo_Fahl at stream.com]

I have wanted a voltage controlled speech synth module for a long time.  About a
year ago, I purchased a Digitalker kit from Jameco, which is a basic speech
synthesizer which seems to be designed for use with a CPU.  This kit is based
around National's MM54104 IC.  The IC has an 8Bit address input bus which allows
up to 256 words/silences to be selected from a speech ROM.

Here is what I'm thinking of doing:

Strapping a simple 8 bit ADC to the address bus, so I can select data via an
input CV or audio.  I want this sucker to babble!
What is a good, easy to use ADC chip that will do this for me?

I want to replace the 4 MHz crystal with a VCO with hopes that I can change the
pitch/sampling rate on the IC. - Is this possible?

I can email a basic application note for the Digitalker to anyone who is
interested.  I appreciate any feedback!

Romeo