Quoth is an old way of saying “said.” You meet it in poems and old stories, not in the shop or the classroom: “Quoth the raven, ‘Nevermore.’” The word order is old too: quoth I, quoth he, quoth she — the verb before the person, which we do not do now with said. Nobody uses it in ordinary talk unless they are joking or putting on an old-fashioned voice. Though actually, it is not a fancy form of quote, and it is not the past of quote. It comes from an old verb meaning “to say,” and this form is only a past: I said / he said. There is no everyday present “I quoth.” If you want “said,” say said; keep quoth for the page where the old voice belongs.