You call them differently because they are different. Auxiliary verbs (also called Primary auxiliary verbs - to be, to have and to do) form tenses and show Aspect. They can also be lexical verbs and they can be inflected. Modal auxiliary verbs

Yes - the references I have equate modals and helping verbs. They shouldn't. The most distinguishing thing about a modal is that it doesn't have an infinitive (there's no "to can go" or "to must go"). Auxiliary (or

I was a bit confused myself in the beginning becuase I thought that modals were just can, could; may, might; will, would; must; shall, should. These verbs are the "classical" modals, but every verb that expresses/describes the modus of a full