While eating in a restaurant, I reprimanded my four-year-old son for speaking with his mouth full . "Mump umn Kmpfhm," was all I heard."Drew," I scolded, "no one can understand a word you're saying. "He says he wants some ketchup," my husband said calmly A woman sitting nearby leaned over and asked, "How in the world did you understand him?" "I'm a dentist," my husband explained.