An easy option is to set up a free account at http://www.pandorabots.com and you can use AIML files from a few different languages. I see you are from Vietnam. Unfortunately, I know of no Vietnamese AIML sets but you could always translate the English ones if you have a couple of months to spare. I’m sure the guys at Pandorabots would appreciate the effort.
If you are feeling adventurous, you could set up a chatbot which would automatically translate from English to Vietnamese using something like google translate? As I don’t know the language, I will give an example in French:
Human: Bonjour, ca va?
(google translate: hello how are you - Bot receives “hello how are you”)
Bot: Very well thank you
(google translate: tres bien, merci - Human receives “tres bien, merci”)
Human: Glad to hear it
.
.
and so on