I was browsing to try and find some ways to make what would essentially be a voice-activated toy. I am completely new to all of this and could use a little guidance. Is it possible that something could be made to respond to a certain phrase with pre-recorded messages? Also, if it can, what parts could be used to fit into something roughly the size of a beer can? any advice or recommendations would be greatly appreciated. Thanks.
Since you can buy voice-activated toys, it would seem possible to make them.
An Arduino can't do voice recognition, but some small commercial modules are available to do that. Google will find them for you.
An Arduino can produce speech (canned phrases using the Talkie library, or there are modules to do that too).
It looks like Sparkfun has a couple of modules for VR & text to speech - probably lots of others out there