The person starting speaks a letter. The next person speaks that letter and adds another letter. The trick is not to spell a word. Exclude people who spell a word. People must have a word in mind when they are adding a letter, or they can bluff. If a person challenges someone as to what word they have in mind that their added letter would lead them to spell then the challenged must say the word or be excluded. If the challenger is shown up then he or she is excluded.
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