native speaker vs talker

native speaker and talker both are nouns.

Word	Noun	Adjective	Verb	Adverb
native speaker	Yes	No	No	No
talker	Yes	No	No	No

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

native speaker: a speaker of a particular language who has spoken that language since earliest childhood
talker: someone who expresses in language; someone who talks (especially someone who delivers a public speech or someone especially garrulous)

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

native speaker (noun)	talker (noun)
a speaker of a particular language who has spoken that language since earliest childhood	someone who expresses in language; someone who talks (especially someone who delivers a public speech or someone especially garrulous)