teller vs talker

teller and talker both are nouns.

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

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

teller: 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 teller include speaker, utterer, verbaliser, verbalizer.

teller (noun)	talker (noun)
an employee of a bank who receives and pays out money	someone who expresses in language; someone who talks (especially someone who delivers a public speech or someone especially garrulous)
an official appointed to count the votes (especially in legislative assembly)
someone who tells a story