Ordinary verb forms are exactly what they sound like:
"You didn't do your homework very early tonight," would be an example of using "do" as an ordinary verb.
Progressive verb forms are used to show that the action is going on at the time indicated by the tense:
"I am answering your question in an attempt to help you with your homework," would be an example of present progressive, and "I was answering your homework question while petting my kitten," would be an example of past progressive.
Emphatic forms, sometimes called the emphatic tenses or emphatic mood, are made with the auxiliary verb "do" in the present or past tense + the base form of the verb:
"He doesn't speak very well."
"I don't agree with you... he does speak very well."
In the second sentence , the speaker uses the emphatic form "does speak" as a way of contradicting the first speaker.