speak vs begin

speak and begin both are verbs.

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

As verbs, begin is a hyponym of speak; that is, begin is a word with a more specific, narrower meaning than speak:

speak (verb)	begin (verb)
express in speech	take the first step or steps in carrying out an action
exchange thoughts; talk with	set in motion, cause to start
use language	begin to speak or say
give a speech to	begin to speak, understand, read, and write a language
make a characteristic or natural sound	achieve or accomplish in the least degree, usually used in the negative
	begin an event that is implied and limited by the nature or inherent function of the direct object
	have a beginning, in a temporal, spatial, or evaluative sense
	be the first item or point, constitute the beginning or start, come first in a series
	have a beginning characterized in some specified way
	have a beginning, of a temporal event