narrator vs talker

narrator and talker both are nouns.

Word	Noun	Adjective	Verb	Adverb
narrator	Yes	No	No	No
talker	Yes	No	No	No

As nouns, talker is a hypernym of narrator; that is, talker is a word with a broader meaning than narrator:

narrator: someone who tells a story
talker: someone who expresses in language; someone who talks (especially someone who delivers a public speech or someone especially garrulous)

Other hypernyms of narrator include speaker, utterer, verbaliser, verbalizer.

narrator (noun)	talker (noun)
someone who tells a story	someone who expresses in language; someone who talks (especially someone who delivers a public speech or someone especially garrulous)