Grammatical categories

[Antonella Conte]

Hi there fellow researchers,

I am presently doing some morphological and syntactic analysis of English
utterances.

I would like to categorize or label the different words used in the
utterances under the traditional parts of speech (noun, verb, adj, adv,
pronoun, etc).  However, this is not as simple as it sounds... at least not
for me.  I hope someone can shed some light on this.

Question 1:
In an utterance like : "I speak Italian" we have "pro-verb"
In an utterance like: "I can speak Italian" we have "pro-modal verb-main verb"
But in an utterance like: "I can"... What is the category of "can"?  Do you
call it a modal verb or a main verb?

Question 2:
How can we categorize "let's" or let us" as in an utterance of the type:
"Let's play hockey" or "Let him eat."  I figure "play" and "eat" are the
main verbs, but what is "let"????? No grammar book supplies me with an
adequate response other than stating that the utterance is imperative, but
this is not what I'm looking for.

Thank you,
Antonella Conte
Université Laval