I was encouraged to speak to students about the vos form when many of them began volunteering in Nicaragua, and my niece used a very helpful description of the voseo, calling it the 'dude' form, one that is even more informal than the tú form of 'you' … and now, http://www.wordreference.com has included the vos form for many of the verb conjugations as well. Thanks for your post !
Thank you, I love the "dude" idea!