rap vs speak

rap is a noun but speak is not a noun.

Word	Noun	Adjective	Verb	Adverb
rap	Yes	No	Yes	No
speak	No	No	Yes	No

As verbs, speak is a hypernym of rap; that is, speak is a word with a broader meaning than rap:

Other hypernyms of rap include talk.

rap (noun)	speak (noun)
the act of hitting vigorously
a reproach for some lapse or misdeed
voluble conversation
genre of African-American music of the 1980s and 1990s in which rhyming lyrics are chanted to a musical accompaniment; several forms of rap have emerged
the sound made by a gentle blow
a gentle blow

rap (verb)	speak (verb)
talk volubly	express in speech
strike sharply	exchange thoughts; talk with
perform rap music	use language
make light, repeated taps on a surface	give a speech to
	make a characteristic or natural sound