The word difficult is an adjective. The noun form is difficulty.
Aphasia
Aphasia
It is more difficult to determine how long the speech will be
Feat is a noun. (a difficult accomplishment)
to regulate speech is to limit it, which is difficult to do without violating the 1st Amendment.
spasmodic dysphonia
oh its really very difficult to describe
The word "difficult" is an adjective. It is used to describe nouns by indicating that something is not easy or requires effort.
The word puzzling is an adjective. It is used to describe something that is difficult to understand.
Pessimist, Optimist, Rhymester, chemist. There are some others, but they'd be difficult to use in speech.
The word cope is a verb. It means to deal with something that is particularly difficult.
preposition A+