teach vs talk

teach is not a noun while talk is a noun.

Word	Noun	Adjective	Verb	Adverb
teach	No	No	Yes	No
talk	Yes	No	Yes	No

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

teach (noun)	talk (noun)
	the act of giving a talk to an audience
	an exchange of ideas via conversation
	idle gossip or rumor
	a speech that is open to the public
	discussion; (`talk about' is a less formal alternative for `discussion of')

teach (verb)	talk (verb)
accustom gradually to some action or attitude	express in speech
impart skills or knowledge to	exchange thoughts; talk with
	reveal information
	use language
	deliver a lecture or talk
	divulge confidential information or secrets