The word illegal is an adjective. It means forbidden by law.
It is an adjective meaning impossible to read.
It is an adverb.
The Freedom of Speech.
part of speech
The part of speech for this particular word is a noun.
adverb
what part of speech is work
what part of speech is beneath
the part of speech sashay is a averb
Did is a verb, and not is an adverb. Didn't is not any part of speech. It's a contraction of did and not.
Adjective
The word speech is a noun.
No, but it's part of a noun which the noun is the part of speech.
Yes, conjunction is a part of speech.