Most textbooks seems to use "volitional" to mean the ~you ~mashou form. If the ~tai form is given a name (which it often isn't), it's usually "desiderative".
You can also find the ~you ~mashou form called "presumptive" or "hortative".
Postby community.japanese » August 18th, 2013 7:55 am
Tracel-san, Dan-san, マイケルsan, thank you very much for brilliant help, Tracel-san and マイケルsan. That's right; "-tai" form is not volitional form. It simply describes "wishes".
Volitional form describes your intentions as well.