Modal is a type of auxiliary verb. The complete list of them are:
- Can/could/be able to
- May/might
- Shall/should
- Must/have to
- Will/would
Another (unnamed?) category of verbs is these 3:
- Have
- Be
- Do
All other verbs are your normal "actions" and are used by themselves as far as I can tell (i.e. "I read the book", just one verb).
My question's first part is, is this all of the modal/helper verbs? Are there any more? What is the complete list?
The main part of the question though is, why these are considered verbs in the first place. Here's why I'm asking that.
(1) I might go to the store.
(2)I possibly go to the store.
(3) I might possibly go to the store.
(4)I should could go to the store.
(5) I should have used to be going to the store.
So (1) is saying "possibly go to the store" basically. But you can't use "possibly" as a verb (2). It is an adverb it looks like (3).
Then, (4), you can't do either. But technically if you break down the meaning, it is a valid thing to say, saying essentially "I should go to the store and I could go to the store.".
Number (5) is just to show this is the max number of verbs I can seem to cram into a sequence.
Why do only these 5 or 8 verbs allow for this direct composition? Why aren't there 100's that have this same feature? What is so special about these?
In my head, I have quite a hard time visualizing these 5 as "actions". It is hard to visualize "may" as an action. Or "should" as an action. So why are they considered actions?
Are there any other areas of research that treats these in novel ways, provides different perspectives, etc.?