Text-to-Speech for Arduino.
This requires an amplifier on the PWM output pin, e.g., this one: http://www.tinyurl.com/magicmouth/
The original implementation was by Clive Webster in Webbotlib (http://webbot.org.uk/iPoint/30.page ).
This was ported to Arduino by Gabriel Petrut (http://www.tehnorama.ro/minieric-modulul-de-control-si-sinteza-vocala/ ).
Stephen Crane modified it to use pins other than pin 10 with the help of this tutorial:
https://sites.google.com/site/qeewiki/books/avr-guide/pwm-on-the-atmega328
See blog articles: http://programmablehardware.blogspot.ie/search/label/tts