Yes and No is a spoken word game similar to Twenty Questions played in Charles Dickens' A Christmas Carol.
English originally used a four-form system up to and including Early Middle English but Modern English has reduced this to a two-form system consisting of just 'yes' and 'no'.
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While Modern English has a two-form system of yes and no for affirmatives and negatives, earlier forms of English had a four-form system, comprising the words yea, nay, yes, and no.
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Georg von der Gabelentz, Henry Sweet, and Wegener have all written on the subject of sentence words, Wegener calling them "Wortsätze".