WHAT THE F
What Swearing Reveals About Our Language, Our Brains, and Ourselves
By Benjamin K. Bergen
271 pp. Basic Books. $27.99.
IN PRAISE OF PROFANITY
By Michael Adams
253 pp. Oxford University Press. $17.95.
Every parent has been there, or will be there soon: the moment when your darling 5-year-old says one of the magic words that can transform a PG movie into an R, or earn an N.B.A. star a $25,000 fine.