How can I program a simple chat bot AI?

Question

I want to build a bot that asks someone a few simple questions and branches based on the answer. I realize parsing meaning from the human responses will be challenging, but how

Answer 1

I think to start this project, it would be good to have a database with questions (organized as a tree. In every node one or more questions). These questions sould be answered with "yes " or "no".

If the bot starts to question, it can start with any question from yuor database of questions marked as a start-question. The answer is the way to the next node in the tree.

Edit: Here is a somple one written in ruby you can start with: rubyBOT