bespeak vs signal

bespeak is not a noun while signal is a noun.

Word	Noun	Adjective	Verb	Adverb
bespeak	No	No	Yes	No
signal	Yes	Yes	Yes	No

As verbs, bespeak and signal are synonyms defined as:

Other synonyms of bespeak include betoken, indicate, point.

bespeak (noun)	signal (noun)
	any nonverbal action or gesture that encodes a message
	any incitement to action
	an electric quantity (voltage or current or field strength) whose modulation represents coded information about the source from which it comes

bespeak (adjective)	signal (adjective)
	notably out of the ordinary

bespeak (verb)	signal (verb)
express the need or desire for	communicate silently and non-verbally by signals or signs
be a signal for or a symptom of	be a signal for or a symptom of