speak vs speaker

speak is not a noun while speaker is a noun.

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

speak (noun)	speaker (noun)
	electro-acoustic transducer that converts electrical signals into sounds loud enough to be heard at a distance
	someone who expresses in language; someone who talks (especially someone who delivers a public speech or someone especially garrulous)

speak (verb)	speaker (verb)
express in speech
exchange thoughts; talk with
use language
give a speech to
make a characteristic or natural sound