Shelly Terrell has recommended a great site where students can communicate with chatbots: http://www.eslfast.com/robot. Developed by Ron Lee, a Chinese artificial intelligence scientist working in LA, the ESL Robots Project creates online electronic tutors to help English language learners practice their productive English speaking and writing skills. Users study the conversations first by reading and listening to them several times, and then practice these conversations with the robot.
Learners can type in a question, and then click the SAY button or hit the ENTER key on their keyboard, and the robot will reply. So far I haven't actually managed to get the robots talking to me in direct response to what I'm typing in, they just respond in writing. Perhaps I'm doing something wrong.
If a learner has speech recognition software installed, such as Dragon Naturally Speaking, he or she can speak into the microphone instead of typing in questions.
The robots are capable of learning. They are being trained by the users in response to the input they receive, so they are getting "smarter" with every "conversation". They have learned many idioms and proverbs. The robots can even point out some spelling and grammatical errors in a learner's writing. So they can also be considered a good tool for ESL students to practice writing.
This project is being developed at Pasadena City College, California, USA.
A second very nice site is A.L.I.C.E. Artificial Intelligence Foundation. While full membership is $99 for a year, you can chat with the D.A.V.E. chat robot for one month for $9.99. For more information on the project, see their blog, http://alicebot.blogspot.com.
Do any of you have experience with chatbots to share?