The word could've is a contraction, a shortened form for could have.
The contraction could've functions as a verb (or auxiliary verb).
The auxiliary verb could have is used to express a possibility in the past.
Example:
I could have passed the exam If I had worked harder.
Or:
I could've passed the exam if I had worked harder.
The part of speech for this particular word is a noun.
The part of speech that the word my is used as is an adjective.
The part of speech for the word diplomacy is a noun.
H is a letter, not a word. To be a part of speech, it needs to be a word.
The part of speech for the word "boulevard" is a noun.
The part of speech for the word civilian is English grammar.
The word speech is a noun.
It is not ANY part of speech, there is no such English word as "stroobly".
The part of speech for this particular word is a noun.
The word speech is a noun.
The word speech is a noun.
The word speech is a noun.